TRAY SEALER AND METHOD FOR OPERATING THE SAME

Abstract

The disclosure relates to a tray sealer comprising an endless conveyor and a sealing station for sealing a tray with a cover film, said sealing station including a sealing-tool upper part and a tray support provided with an edge support for accommodating a tray edge. The disclosure is characterized in that the edge support comprises at least two edge support sections which are movable relative to one another. The disclosure also relates to a suitable method for operating a tray sealer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to German patent application number DE 10 2010 056 316.1, filed Dec. 27, 2010 which is incorporated by reference in its entirety.

TECHNICAL FIELD

The disclosure relates to a tray sealer as well as to a method of operating a tray sealer for sealing a tray.

BACKGROUND

DE 10 2008 030 510 A1 discloses a tray sealer in which conveyor belts are provided for conveying trays to a work station for sealing the trays. The trays are picked up from the conveyor belts by means of a gripper system and conveyed into the work station where they are released. The gripper system must here be located outside of the work station before a sealing-tool lower part presses the trays upwards against a sealing-tool upper part for sealing the respective tray with a cover film so as to form a package. The gripper system must execute a plurality of different successive movements in the course of this process. For gripping the trays, two gripper arms are moved towards one another and, subsequently, the gripper arms are moved in the direction of production into the work station and then out of the sealing station so that said sealing station can be closed. In order to obtain an air-tight chamber in which the trays can be evacuated prior to sealing, the sealing-tool lower part and the cover film seal off against the sealing-tool upper part. Also, in order to allow also the closed packages to be conveyed out of the tray sealer, a further conveyor belt is required after the work station.

DE 102 37 933 A1 describes a sealing station of a tray sealer in which the sealing-tool lower part comprises a chamber lower part and a tray support. The tray support comprises a frame for clamping a cover film to the sealing-tool upper part and a support member for accommodating the tray edge of a tray. The frame and the support member are connected to one another via guides such that they can be adjusted relative to one another so as to seal off the cover film against the tool upper part, and so as to deform the cover film upwards into the sealing-tool upper part by means of an upward applied vacuum. The sealing member is then able to lift the tray with a projecting product in the direction of the sealing-tool upper part until the tray has reached the sealing position. The chamber lower part is movable relative to the tray support and defines an evacuable chamber at its upper work position, at which the cover film is clamped between the chamber lower part and the sealing-tool upper part.

SUMMARY

It is an object of the present disclosure to provide a tray sealer having a simpler structural design.

According to a first aspect of a tray sealer according to the present disclosure, the tray sealer comprises an endless conveyor and a sealing station for sealing a tray with a cover film, the sealing station including a sealing-tool upper part and a tray support. The tray support is provided with an edge support for accommodating a tray edge, and at least two edge support sections which are movable relative to one another. Thus, one or several trays can be conveyed into the sealing station and below the sealing-tool upper part by means of the conveyor, for example, in the form of a conveyor belt or a cleated chain (clamping chain). The conveyor may preferably also extend beyond the sealing station, possibly up to the end of the tray sealer or beyond the end, so as to supply the trays sealed with a cover film to a sequence of further production steps. Due to the implementation of the tray support with two edge support sections, the edge support sections can approach the tray from two opposed sides and can be united so as to pick up the tray from the conveyor and move it against the sealing-tool upper part and the cover film disposed therebetween.

Advantageously, the endless conveyor is permanently provided within the sealing station and below the sealing-tool upper part, in contrast to known gripper systems, which must be removed from the sealing station prior to the sealing process. This allows a simple structural design.

The conveying speed is preferably controlled by a controller of the tray sealer. The conveyor is not limited to the tray sealer with its sealing station alone, but it may also extend far into the upstream production flow so as to pick up empty trays which are then filled with products.

According to a further aspect of a tray sealer according to the present disclosure, the tray sealer comprises an endless conveyor and a sealing station for sealing a tray with a cover film, the sealing station including a sealing-tool upper part and a tray support. The tray support is provided with an edge support for accommodating a tray edge, and the endless conveyor is permanently provided within the sealing station and below the sealing-tool upper part. This allows a simple structural design. The conveying speed is preferably controlled by a controller of the tray sealer.

The edge support may comprise at least two edge support sections which are movable relative to one another. On the basis of this advantageous implementation of the tray support in the form of two edge support sections, the edge support sections can approach the tray from two opposed sides and they can be united for picking up the tray from the conveyor and moving it against the sealing-tool upper part with the cover film disposed therebetween.

In one embodiment, only one drive is provided, the drive being used for the closing movement of the edge support sections relative to one another as well as for lifting the tray by means of the tray support. The tray sealer can thus be realized at a reasonable price.

According to an expedient embodiment, the edge support sections are each provided with a seal, which, when the edge support sections have been united so as to form an edge support as a tray support, press the tray with the cover film against the sealing-tool upper part for the purpose of sealing.

In one embodiment, a chamber lower part is provided, the chamber lower part comprising two chamber parts which are movable relative to one another. In this embodiment, the chamber parts may be provided below the sealing-tool upper part and laterally of and/or above the endless conveyor. The two chamber parts are thus able to move towards one another and into contact with the tray and to execute also a movement in the direction of the sealing-tool upper part.

According to an expedient embodiment, a seal is provided for hermetically sealing the chamber parts relative to one another. After having been united, the two chamber parts form, in a particularly advantageous manner, a chamber lower part and allow, thus, in combination with the sealing-tool upper part, the formation of a hermetically sealed and evacuable chamber. Foodstuffs can thus be packaged under a vacuum or a modified atmosphere so as to guarantee a long shelf life.

According to one embodiment, the respective chamber parts, and/or the respective edge support sections, are substantially symmetrical to one another in relation to a plane extending parallel to a conveying direction and orthogonally to a conveying plane of the endless conveyor. This has the effect that the moments of inertia are identical on both sides.

It will also be of advantage when the edge support sections and the chamber parts are adapted to be connected via a common mechanism by means of levers and spring elements so as to allow a synchronous movement of both sides of the mechanism.

According to one embodiment, the mechanism which is provided for the edge support sections and the chamber parts in common has a respective horizontal and a respective vertical movement component so that the tray can be engaged on its side and lifted.

According to one embodiment, a plurality of parts which are movable relative to one another, such as the edge support sections and the chamber parts, have a drive in common so as to provide an economy-priced sealing station whose sequence of movements can be controlled easily.

The edge support sections and/or the chamber parts are, in an advantageous manner, movable relative to one another by means of guides which are oriented parallel to the conveying plane of the endless conveyor.

A method of operating a tray sealer according to the present disclosure comprises conveying a tray into a sealing station on an endless conveyor to a position between a sealing-tool upper part and a tray support, providing on the tray support an edge support including at least two edge support sections, moving the edge support sections into contact with the tray from two sides, thus uniting the sections so as to form the tray support, and providing a cover film located between the tray and the sealing-tool upper part to seal the tray. This method allows trays to be conveyed on only one conveyor, e.g. in the form of a conveyor belt or a cleated chain, through the machine and into as well as out of the sealing station. There is no need for additional stops and undesirable accelerations, such as those required in the case of gripper systems, which pick up the trays from a supply belt and transfer them to the sealing station and which, when the trays have been sealed, transfer them to a discharge belt.

One embodiment of the method includes lifting the edge support sections and the tray upward to the sealing-tool upper part.

One embodiment is so conceived that, in relation to the conveying direction of the endless conveyor, the edge support sections move orthogonally towards one another and towards the tray. The edge support sections occupy a parking position laterally next to the conveyor and, from this position, they can be moved into contact with the tray with simultaneous movements so that the distances to be covered are as short as possible, whereby the performance of the tray sealer will be increased.

After having been united, the edge support sections define a tray support in an advantageous manner, and this tray support accommodates the tray, preferably the tray edge. The tray support lifts the tray from the conveyor in the direction of the sealing-tool upper part. It is advantageous that, during such lifting, the trays have applied thereto only vertical acceleration forces, which, other than acceleration forces occurring in the conveying direction, are uncritical with respect to liquid products contained in the trays.

Preferably, the closing movement of the edge support sections is executed before the tray is lifted by the edge support sections and the tray support, respectively. This guarantees that the edge support sections will first form the tray support together and that the subsequent vertical movement of the tray will take place smoothly and with process reliability without being influenced by still occurring transverse movements of the edge support sections.

According to one embodiment, a chamber lower part is provided, said chamber lower part comprising two chamber parts, and the two chamber parts being moved below the sealing-tool upper part and above the endless conveyor towards one another in such a way that the two chamber parts define the chamber lower part. The chamber lower part is here located below the tray lifted by means of the tray support, and it is also moved in the direction of the sealing-tool upper part so as to be able to form a chamber with said sealing-tool upper part.

The chamber lower part is moved against the sealing-tool upper part and defines, in an advantageous manner, a chamber together with said sealing-tool upper part, in which a vacuum and/or a modified atmosphere can be created. It is thus possible to produce evacuated and gas-flushed packages, such as, for example, packages for foodstuffs.

The movements of the edge support sections and the chamber parts preferably take place simultaneously so as to minimize processing time and so as to increase the productivity of the tray sealer.

According to a particularly advantageous embodiment, the movements of the edge support sections and of the chamber parts are carried out by means of only one drive so as to provide a simple and efficient method.

In the following, advantageous embodiments of the tray sealer according to the present disclosure and of the method according to the present disclosure are explained in more detail with reference to the below drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a tray sealer according to the present disclosure;

FIG. 2 is a top view of the tray sealer;

FIG. 3 is a schematic view of the tray sealer in the direction of production at a basic position of the sealing station;

FIG. 4 is a schematic view according to FIG. 3 with united edge support sections;

FIG. 5 is a schematic view according to FIG. 3 at a sealing position;

FIG. 6 is a schematic view of a tray sealer variant according to the present disclosure;

FIG. 7 is a schematic view of the tray sealer according to FIG. 6 in the direction of production at a basic position of the sealing station;

FIG. 8 is a schematic view according to FIG. 7 with united edge support sections;

FIG. 9 is a schematic view according to FIG. 7 with lifted tray;

FIG. 10 is a schematic view according to FIG. 7 with united chamber parts; and

FIG. 11 is a schematic view according to FIG. 7 at a sealing position.

DETAILED DESCRIPTION

Corresponding components are designated by corresponding reference numerals throughout the figures.

FIG. 1 shows a schematic view of a tray sealer 1 comprising an endless conveyor 2 and a sealing station 3. The sealing station 3 comprises a sealing-tool upper part 4 and a tray support 5. The tray support 5 is provided with an edge support 6, which is divided into two symmetrically configured edge support sections 6a and 6b. The edge support sections 6a and 6b are movable relative to one another by means of mechanisms 7a and 7b. A drive, which is not shown, drives at least one shaft 8a, 8b. The shafts 8a and 8b, respectively, are connected to the edge support sections 6a and 6b, respectively, via the mechanisms 7a and 7b. A tray 9, which was conveyed into the sealing station 3 in a direction of production R, is disposed on the endless conveyor 2, which is here shown as a conveyor belt and which may alternatively be implemented as a cleated chain.

In FIG. 2 the edge support 6, i.e., the edge support sections 6a and 6b, are provided with a groove 10, which is used for accommodating therein a tray edge 9b (cf. FIG. 3) of the tray 9 and for allowing a cut, which is not shown and in the case of which a cutting knife can cut a cover film outside of the tray edge.

FIG. 3 shows the tray sealer 1 in the direction of production R. The sealing station 3 occupies here a basic position at which the tray 9 was conveyed on the conveyor 2 into the sealing station 3, and the edge support sections 6a and 6b are located laterally next to the tray 9 at a position of rest.

FIG. 4 shows the position of the edge support sections 6a and 6b after the latter have been moved towards one another by means of the mechanism 7a, 7b, so that, in a position of contact, they together define the tray support 5. At this position, the tray support 5 is located below the tray edge 9b of the tray 9 and above the conveyor 2. The mechanism 7a, 7b is here implemented as a combination comprising the levers 11a, 1 lb, 12a and 12b and a guide 13 as well as the shafts 8a, 8b in the form of a toggle lever lifting mechanism. The mechanism 7a, 7b causes a simultaneous movement of the edge support sections 6a and 6b towards one another in the horizontal direction by means of the guide 13, and a vertical upward movement by means of the levers 11a, 11b, 12a and 12b. The movement of the toggle lever lifting mechanism can be effected by synchronized movements of the shafts 8a and 8b in opposite directions, by two separately driven shafts 8a, 8b, or by a synchronization of the levers 11a and 12a with the levers 11b and 12b relative to one another, as is known to a person skilled in the art.

During a further vertical movement in the direction of the sealing-tool upper part 4, the tray support 5 lifts the tray 9 at the tray edge 9b and presses the tray edge 9b, as shown in FIG. 5, with a cover film which is not shown, or a cover that has already been formed, against the sealing-tool upper part 4 so as to seal the cover film or the cover onto the tray edge 9b and form a closed package.

A further variant according to the present disclosure allows a tray to be sealed under vacuum so as to meet, for perishable products such as food, high demands on a long shelf life by minimizing the oxygen content in the package.

In FIG. 6 a further variant of the tray sealer 1′ is so conceived that two chamber parts 14a and 14b, which are coupled to the mechanism 7a, 7b, are provided in addition to the edge support sections 6a and 6b.

FIG. 7 shows the tray sealer l′ in the direction of production R. The sealing station 3 is here at a basic position at which the tray 9 has been conveyed on the conveyor 2 into the sealing station 3, and the edge support sections 6a and 6b as well as the chamber parts 14a and 14b occupy a position of rest laterally next to the tray 9 and the conveyor 2. The chamber parts 14a and 14b are connected to the guide 13, and the edge support sections 6a and 6b are connected to additional guides 15a and 15b. The guides 15a and 15b are connected to the chamber parts 14a and 14b.

FIG. 8 shows a first movement of the toggle lever lifting mechanism in the case of which the levers 11a, 11b, 12a and 12b move, via the mechanism 7a, 7b, relative to one another such that the chamber parts 14a and 14b, as well as the edge support sections 6a and 6b, are moved substantially horizontally towards one another until the edge support sections 6a and 6b enter into contact and define the tray support 5. A vertical movement component of the edge support sections 6a and 6b is also possible as long as the tray support 5 defined is still located below the tray edge 9a.

FIG. 9 shows a further position at which the tray 9 has been accommodated in and lifted by the tray support 5. The bottom surfaces of the chamber parts 14a and 14b are located above the conveyor 2 so that the two chamber parts 14a and 14b can be moved towards one another, as can be seen in FIG. 10. In so doing, the chamber parts 14a, 14b define a chamber lower part 16 such that the contact areas of the chamber parts 14a, 14b are hermetically sealed, e.g. by means of a silicone seal. The force that has to be applied for this purpose is produced via the mechanism 7a, 7b, which holds the chamber parts 14a and 14b together as chamber lower part 16. The continued movement of the mechanism 7a, 7b in the same direction has the effect that the tray support 5 with the tray 9 and the chamber lower part 16 are raised up to the sealing-tool upper part 4. The movement of the chamber lower part 16 acts here against the sealing-tool upper part 4.

The sealing-tool upper part 4 comprises a sealing frame, which is not shown, and a chamber upper part 17. The chamber upper part 17 is pressed upwards against the springs 18 by the chamber lower part 16 and the cover film clamped therebetween. The sealing-tool upper part 4 and the chamber upper part 17 define, together with the chamber lower part 16, an evacuable chamber which is hermetically sealed by means of one or a plurality of seals, preferably silicone seals, and the cover film. In said chamber the package can be evacuated or the atmosphere modified so as to achieve the longest possible shelf life of the product to be packed. The sealing frame is moved relative to the chamber upper part 17 against the tray 9 for executing the closing process and, in so doing, it presses the cover film against the tray 9, under application of heat, in the area of the sealing seam to be formed.

The movements of the mechanism 7a, 7b according to FIG. 7 to FIG. 11 always take place in the same direction and can be effected by a single actuator driving the levers 11a, 12a and 11b, 12b on both sides of the toggle lever lifting mechanism. Via springs 19 (cf. FIG. 8 or 9) or other tension means, the horizontal and vertical movements of the edge support sections 6a, 6b and chamber parts 14a, 14b can take place simultaneously and/or successively. A synchronization of the levers 11a, 12a and 11b, 12b of both sides of the toggle lever lifting mechanism is of advantage so that the edge support sections 6a, 6b and the chamber parts 14a, 14b will meet centrally to the toggle lever lifting mechanism and so that also the tray 9 will be located centrally thereto on the conveyor 2 so as to avoid unnecessary lateral impacts on the tray 9 or lateral movements of the tray 9.

The work station 3 is also suitable for accommodating therein two or more trays 9, the dimensions of the work station 3 being then adequately enlarged in the direction of production R. The trays 9 are conveyed by the conveyor 2 into the work station 3 such that they are spaced apart at a predetermined distance, according to the edge support sections 6a and 6b.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

1. A tray sealer comprising an endless conveyor and a sealing station for sealing a tray with a cover film, said sealing station including a sealing-tool upper part and a tray support provided with an edge support for accommodating a tray edge, wherein the edge support comprises at least two edge support sections which are movable relative to one another.

2. A tray sealer according to claim 1, wherein the endless conveyor is permanently provided within the sealing station and below the sealing-tool upper part.

3. A tray sealer according to claim 1, wherein there is provided one drive which is used for a closing movement of the edge support sections towards one another as well as for lifting the tray by means of the tray support.

4. A tray sealer according to claim 1, wherein the edge support sections are each provided with a seal.

5. A tray sealer according to claim 1, wherein a chamber lower part is provided, said chamber lower part comprising two chamber parts which are movable relative to one another.

6. A tray sealer according to claim 5, wherein the two chamber parts are provided below the sealing-tool upper part and laterally of and/or above the endless conveyor.

7. A tray sealer according to claim 5, wherein a seal is provided for hermetically sealing the chamber parts against one another.

8. A tray sealer according to claim 7, wherein the chamber lower part is connectable to the sealing-tool upper part so as to form a hermetically sealed and evacuable chamber.

9. A tray sealer according to claim 5, wherein, in relation to a plane extending parallel to a conveying direction and orthogonally to a conveying plane of the endless conveyor, the respective chamber parts and/or the respective edge support sections are substantially symmetrical to one another.

10. A tray sealer according to claim 5, wherein the edge support sections and the chamber parts are adapted to be connected via a common mechanism by means of levers and spring elements.

11. A tray sealer according to claim 10, wherein the mechanism which is provided for the edge support sections and the chamber parts in common has a respective horizontal and a respective vertical movement component.

12. A tray sealer according to claim 5, wherein a plurality of parts which are movable relative to one another, such as the edge support sections and the chamber parts, have a drive in common.

13. A tray sealer according to claim 5, wherein the edge support sections and/or the chamber parts are movable relative to one another by means of guides which are oriented parallel to the conveying plane of the endless conveyor.

14. A tray sealer comprising an endless conveyor and a sealing station for sealing a tray with a cover film, said sealing station including a sealing-tool upper part and a tray support provided with an edge support for accommodating a tray edge, wherein the endless conveyor is permanently provided within the sealing station and below the sealing-tool upper part.

15. A tray sealer according to claim 14, wherein the edge support comprises at least two edge support sections which are movable relative to one another.

16. A method of operating a tray sealer which comprises an endless conveyor and a sealing station, including the steps of conveying a tray on the conveyor into the sealing station to a position between a sealing-tool upper part and a tray support, providing the tray support with an edge support including at least two edge support sections, moving the edge support sections into contact with the tray from two sides, the edge support sections being thus united so as to form the tray support, locating a cover film between the tray and the sealing-tool upper part, and sealing the cover film to the tray.

17. A method according to claim 16, further including the step of lifting the edge support sections to thereby lift the tray upward to the sealing-tool upper part.

18. A method according to claim 16, further including the step of moving the edge support sections orthogonally in relation to the conveying direction of the endless conveyor towards one another and towards the tray.

19. A method according to claim 16, wherein after having been united, the edge support sections provide the tray support, and the tray support accommodates the tray.

20. A method according to claim 16, including the step of closing the movement of the edge support sections before the tray is lifted.

21. A method according to claim 16, further including the step of providing a chamber lower part comprising two chamber parts, and moving the two chamber parts below the sealing-tool upper part and above the endless conveyor towards one another in such a way that the two chamber parts define the chamber lower part.

22. A method according to claim 21, further including the steps of moving the chamber lower part against the sealing-tool upper part, and connecting the chamber lower part to the sealing-tool upper part so as to form a hermetically sealed and evacuable chamber.

23. A method according to claim 21, wherein the movements of the edge support sections and of the chamber parts takes place simultaneously.

24. A method according to claim 16, wherein the movements of a plurality of parts which are movable relative to one another are carried out by means of only one drive.