MXPA01000761A

MXPA01000761A - Package sealing anvil.

Info

Publication number: MXPA01000761A
Application number: MXPA01000761A
Authority: MX
Inventors: Michael Gorlich
Original assignee: World Class Packaging Syst
Priority date: 1998-07-22
Filing date: 1999-07-19
Publication date: 2002-04-08
Also published as: WO2000005135A1; CA2352257A1; AU5218499A; EP1098814A1; JP2002521277A

Abstract

A sealing anvil (18) for sealing film to packages, such as trays, includes a replaceable anvil with a resilient upper surface (20). The anvil may be connected to a guide (22) which guides the tray or other package into position on top of the anvil.

Description

YUNQUE TO SEAL PACKAGING FIELD OF THE INVENTION This invention relates generally to the sealing of plastic films on packaging and particularly to techniques for sealing film on relatively rigid plastic packages.

BACKGROUND OF THE INVENTION Food products such as meat are commonly contained in a foam tray covered by a plastic film. With more rigid plastic materials used to make trays, some difficulties result in obtaining a good seal between the film and the tray. A relatively rigid tray may be slightly irregular and these irregularities may result in improper sealing, in particular locations, between the film and the tray.

REF. : 126766 This difficulty can be addressed by using a sealing plate or anvil which includes a T-shaped inner ring which provides a sealing surface installed on bearings between the underside of the tray boss and the tray. sealed or anvil. However, this solution has its own disadvantages. It is not common for the inner ring to be imperfectly fixed within its supporting surface. This can cause the upper surface of the inner ring to be irregular when the tray is sealed. Again, the result may be inadequate sealing between the film and the tray. In addition, the inner rings in the form of T tend to give in the center (where they are less supported) resulting in an inadequate seal in the center and a pair of sealed regions that extend to either side. This can also result in improper sealing. Accordingly, there is a continuing need for an anvil to be sealed which facilitates reliable sealing between the tray and the film particularly with relatively rigid trays or other packages.

DESCRIPTION OF THE INVENTION According to one aspect, a sealing surface for a machine for sealing film on the sealing projection of a package includes a support and a sealing anvil. The anvil is adapted to conform to the sealing protrusion. The anvil includes a rigid element and a flexible element secured to the rigid element. The anvil is removably secured to the support. According to another embodiment, a sealing station for a sealing film machine to the seal projection of a package includes a sealing anvil and a guide. The anvil has a surface adapted to mate with the sealing protrusion. The guide is secured to the anvil at a point spaced from the surface of the sealing anvil.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of an embodiment on a sealing station according to the present invention; Figure 2 is an enlarged perspective view of the sealing anvil shown in Figure 1; and Figure 3 is a cross-sectional view of a portion of the station shown in Figure 1, showing the interaction between a tray and the guide end according to the embodiment shown in Figure 1.

DETAILED DESCRIPTION Referring to Figure 1, a station of. seal 10 for a packaging machine includes an upper cover 12 and a lower cover 14. The upper and lower covers 12 and 14 can be moved towards and away from each other to capture a film 34 between the two covers. A sealing bar 26 can be mounted on the upper cover 12 to seal the film 34 to a tray or other portion of the package 28. More particularly, the film 34 is sealed to the projection of the tray 32 which extends around the peripheral edge of the tray. The tray 28 is placed on a sealing anvil 18 which is in turn supported on a guide 16. The sealing anvil 18 is removably connected to the guide 16 by threaded fasteners 24. A guide edge 22 is defined when it extends outwardly. of the sealing anvil 18 and spaced down from its edge or upper end. The sealing anvil 18 may include a sealing cushion 20 on its upper end, arranged to couple the upper surface of the projection of the tray 32 below the sealing bar 26. The sealing buffer 20 can be made of a variety of flexible or resilient materials including silicon rubber. In a desirable embodiment, the silicon rubber can be coated on the sealing anvil 18 and pressure and cured by heat in place. The anvil 18 can be made of aluminum. When the film 34 is sealed to the upper surface of the projection of the tray 32, a packaged item 36 may be contained within the package in a desired atmosphere. Subsequent stations may be responsible for film edge cuts and implement other packing functions.

The anvil 18 shown in Figure 2 can be formed from a white or aluminum model of another metallic material coated with a resilient material to form the sealing cushion or cushion 20. The desired shape to conform to the tray 28 or another packing projection 32 can then be defined from the model or target. In an advantageous embodiment, a programmable water jet can be used for cold cutting of the shape shown in Figure 2 from the model or target. Because of its ability to cold cut, the. The integrity of the cushion or sealing cushion 20 is not affected by the cutting operation. In this way, a carefully shaped sealing anvil can be formed which can then be secured to the sealing station. If the anvil 18 wears out, perhaps because the cushion or cushion 20 fails, the sealing anvil 18 can be easily replaced by undoing the threaded fasteners 24 and providing a new anvil 18. Referring now to Figure 3, it is illustrated the operation of the guide edge 22. When the tray 28 initially moves towards the guide 16, its tapered lower end 3 6 is first guided by the anvil 18 extending upwardly. As the tray portion 36 extends downwardly, the lowermost end 37 eventually engages the extending edge or guide end 22. The free ends of the guide end 22 have a smaller opening than that presented by the ends of the sealing anvil 18. This provides a guiding action which causes the tray 28 to self-pack in the sealing station. In many cases it is not necessary to further push the tray into position. The guiding effect initially achieved by the anvil 18 and subsequently by the sealing ends or edges 22 extending outward, causes the tray to pack exactly as shown in Figure 1 in the position, using only gravity forces in many cases. From the position shown in Figure 1, with the tray 28 seated in the sealing station 10, the guide end 22 engages a central region 38 of the sides of the tray 40. For example, the guide edge 22 can attach a unpacking feature commonly used in many trays. The present invention is particularly useful in relation to relatively rigid trays. Although the provision of the sealing cushion or cushion 20, a good seal can be made completely around the periphery of the tray. Even if the tray has some irregularities, the downward force applied by the sealing bar 26 may be distributed around the projection 32, resulting in a uniform seal around the entire periphery. Because the anvil 18 is replaceable, the design can achieve substantial cost savings since it is not necessary to replace the complete guide and the anvil but only the anvil 18 itself needs to be replaced. In addition, although the provision of the guide edge or end 22, the input tray or other package can be guided to the position to expedite the sealing operation or facilitate further sealing by decreasing the need for additional steps to place the tray or package in the sealing station. Although the present invention has been described with respect to a single embodiment, those skilled in the art will appreciate numerous modifications and variations thereof. It is intended that the appended claims cover all modifications and variations that fall within the true spirit and scope of the present invention.

It is noted that in relation to this date the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property

Claims

1. A sealing surface for a packaging machine for sealing a film on a sealing projection of a package characterized in that it comprises: a support; and a sealing anvil adapted to conform to the sealing protrusion, the anvil including a rigid element and a resilient element secured to the rigid element, the anvil is removably secured to the support, the resilient element formed by a resident material deposited on the rigid element.

2. The surface according to claim 1, characterized in that the rigid element and the flexible element are cut as an integral unit.

3. The surface according to claim 2, characterized in that the rigid element and the resilient element are cut by a water jet cutting system.

4. The surface according to claim 1, characterized in that the support includes a guide edge or end arranged generally perpendicular to the rigid element.

5. The surface according to claim 4, characterized in that the guide end extends internally relative to the rigid element.

6. The surface according to claim 1, characterized in that the anvil is secured to the support by a threaded fastener.

7. The surface according to claim 5, characterized in that the guide end defines a passage with a smaller cross section than the sealing anvil.

8. The surface according to claim 1, characterized in that the support includes a guide edge or end adapted to couple the package when the package is made to fall in engagement with the sealing anvil and to guide the projection of the package in engagement with the sealing anvil .

9. A method for sealing a film to a tray over a sealing projection comprising: moving the tray towards a sealing anvil; guide the tray in alignment with the anvil before the tray engages the anvil; and attach the tray on the anvil for sealing.

10. The method according to claim 9, characterized in that it includes flexibly supporting the projection of the tray above the anvil. • »

11. The method according to the rei indication 9, characterized in that it includes placing a shock absorbing material on a metal model, and cutting the resilient material and the metallic model using a water jet cutter.

12. The method according to claim 9, characterized in that it includes removing the anvil and replacing the anvil. PACKAGING SUMMARY OF THE INVENTION An anvil seal (18) for sealing the film to packages, such as trays, includes a replaceable anvil with a resilient top surface (20). The anvil can be connected to a guide (22) which guides the tray or other package towards the upper position of the anvil.