Patent Application
20130340396
This Application claims priority to German Application Number 102012012481.3 filed Jun. 22, 2012, to Jurgen Prasenz and Jochen Make entitled “Sealing Device for a Tray Sealer,” currently pending, the entire disclosure of which is incorporated herein by reference.
The invention relates to a sealing device for a tray sealer to seal trays containing products with a film web, such as food articles, as well as to a method of operating such a sealing device.
DE 10 2005 035 476 A1 discloses a sealing device in which a film web is clamped on a sealing-tool upper part by a clamping plate. A cutting knife arranged in the sealing-tool upper part carries out a cutting movement such that the cutting knife dips into an opening provided in the clamping plate and cuts a piece of film out of the film web before the film is attached to a tray edge and sealed, by use of a sealing plate. In this known inside-cut process, the film is cut prior to being sealed such that the dimensions of the cut film correspond to the sealed area so that the film does not extend up to the outermost edge of a tray, and no film or only a very small part of the film projects beyond the sealed seam after sealing. This technique forms a package having pleasing and neat appearance. Since the film web extends between the sealing-tool upper part and the clamping plate and is pinched therebetween, the clamping plate is resiliently guided in the sealing-tool upper part. This embodiment makes it difficult to thread in a new film web after a change of films, and is in some cases obstructive insofar as the residual film grid of the film web may get stuck during film transport. In addition, if process irregularities occur, such as a product projecting beyond the tray edge of a tray, and the sealing device presses the product against the clamping plate, then the clamping plate may be easily damaged.
Other sealing devices are known in the art, such as those described in DE 10 2006 061 309 A1, DE 102 37 933 A1, or DE 10 2008 057 609 A1.
It is the object of the present invention to provide an improved sealing device of a tray sealer and a method of operating such a sealing device, which avoid the above shortcomings in the art.
The sealing device according to the present invention comprises a sealing-tool lower part and a sealing-tool upper part, the sealing-tool lower part including a tray holder and the sealing-tool upper part including a sealing plate and a cutting knife The sealing device may include the tray holder having a cutting channel integrated therein and the cutting knife can dip or be inserted into the cutting channel for cutting a film web. This cutting channel may be defined in that the tray holder includes a reception area as a support for an edge of a tray to be sealed and in that said reception area may be offset by at least five millimeters (5 mm) in a direction away from the sealing-tool upper part relative to a support surface (or bearing surface) on which the film web of the top film can rest outside of the tray. Thus, a cutting channel may be formed, which does not merely extend as an annular track around the tray, but into which the tray can be immersed as a whole. This provides the enormous advantage that a clamping plate, which has previously been resiliently attached to the sealing-tool upper part by means of guide units, may no longer be required in a sealing device. The present sealing device can be implemented with a simpler structural design and enhanced process reliability, and the film web need no longer be threaded in, but can simply be passed between the sealing-tool upper part and the sealing-tool lower part in the open condition of the tool.
According to one embodiment, the cutting channel is substantially arranged concentrically with or may be congruent with the reception area of the tray holder so that a package having an aesthetic appearance can be produced.
Another embodiment includes parallel to a direction of movement of the cutting knife, a distance of three-tenths of one millimeter (0.3 mm) to three millimeters (3 mm) may be provided between the cutting knife and the edge of the cutting channel so as to guarantee a high film cutting quality.
The cutting channel may be arranged above the reception area for an edge of the tray to be held so as to prevent the cutting knife from coming into contact with the tray.
The dimension of the cutting channel corresponds at least to the external dimension of a tray.
Preferably, the tray holder includes a plurality of cutting channels so that a multiple split-up tool (i.e. a tool for simultaneously processing a plurality of trays) can be provided for accomplishing a high packaging performance.
In further embodiments of the present sealing device may include the offset of the reception area relative to the support surface being at least six millimeters (6 mm), and preferably six millimeters (6 mm) to ten millimeters (10 mm), in a direction away from the sealing-tool upper part. Tests have shown that an offset in the range of eight millimeters (8 mm) to nine millimeters (9 mm), in particular eight and one-half millimeters (8.5 mm), may be particularly advantageous.
A method according to the present invention for operating the above-described sealing device may include cutting of the film web using the cutting knife dipped or inserted into the cutting channel of the tray holder; therefore, this method does not require the use of a clamping plate.
The film web may be pinched or compressed between the sealing-tool upper part and the tray holder before it is cut, so as to support the cutting process and allow evacuation of the chamber defined by the sealing-tool upper part and the sealing-tool lower part.
Preferably, the cutting knife remains above a sealing plane when the film web is cut in the cutting channel, but other configurations may be used.
According to another embodiment, the cut film may be taken hold of by the sealing plate, when the latter moves towards the tray holder, and pinched or compressed onto the tray, so as to seal the film onto the tray in the sealing plane for allowing film dimensions that project only a small distance beyond the sealed seam. This configuration may provide the benefit of producing a package having an aesthetic appearance.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.
In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith in which like reference numerals are used to indicate like or similar parts in the various views:
a is a blown up detailed side view of the cutting channel of the sealing device of the tray sealer of
Identical components are provided with identical reference numerals throughout the figures.
The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures.
The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.
A sealing-tool lower part 6 including a tray holder 7 is arranged below the film web 2.
The tray holder 7 is provided for accommodating two trays 8, the trays 8 being placed with their tray edge 9 (best shown in
The tray holder 7 includes a cutting channel 13 above each reception area 10. This cutting channel 13 is defined in that the reception area 10, which is able to carry the tray edge 9, exhibits an offset V of at least five millimeters (5 mm), preferably between six millimeters (6 mm) and ten millimeters (10 mm), relative to a support surface (or bearing surface) 13a of the tray holder 7. The support surface 13a is defined in that the film web 2, i.e. the top film 2, rests thereon, when the sealing device 1 is closed. This explanation shows clearly that the cutting channel 13 according to the present invention is, contrary to the prior art, not a groove that externally surrounds the tray 8, but the cutting channel is here a recess in the tray holder 7 into which the tray is lowered until it rests on the reception area 10. The offset V guarantees that, even when a tray 8 has been placed into the tray holder 7, a sufficient amount of space is left above this tray for defining an evacuation gap having a dimension of one millimeter (1 mm) to two millimeters (2 mm), and that, in addition, the cutting knives 4, which normally have serrated cutting edges, will also be able to cut a downwardly yielding film web 2 without any risk of penetrating into the material of the tray 8 and damaging the tray 8. With an offset of at least five millimeters (5 mm) a very high process reliability can be accomplished, even if and in particular if the materials of the tray 8 and/or the film web 2 used are comparatively thick and cannot be handled easily.
While in use, the sealing device 1 is operable to seal one or more trays 8 in the following manner At the outset of each operating cycle, the sealing device 1 is open and trays 8 filled with the product in question are placed into the tray holder 7. The film web 2 is transported far enough in the direction of production P of the tray sealer for its residual film grid 14 to be located outside the sealing device 1 or at least outside the areas of the cutting knives 4.
Subsequently, the sealing device 1 is closed, as shown in
Subsequently, the sealing plate 5 is moved downwards, as shown in
The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102012012481.3 | Jun 2012 | DE | national |
