Process and Equipment for Shaping Container Seals

This invention relates to a process for shaping container seals (closures or caps) consisting of an electrically conducting metal, especially aluminum or a light-metal alloy.

It is known that one can seal containers with metal caps that are folded mechanically upon or around the container opening or that are crimped on. This known process does not result in a reliable seal, for example, of a beverage bottle, because of the folds. This is why, to make the seal tight, there is an additional sealing or gluing on the container edge that, on the one hand, is expensive and, on the other hand, causes problems during the recycling of the metal because it burns up as the metal is melted down and thus releases toxic or corroding gases.

The purpose of the invention is to provide a process and equipment, suitable for implementing the process, by which means it is possible in a technically perfect manner to close up containers, such as, especially, milk bottles and other suitable containers, using container seals made of an electrically conducting metal, without the use of any mechanical tools.

A primary objective of the invention is to provide a process for applying container seals (closures or caps) of metal by deforming or shaping them, characterized by subjecting them to an electromagnetic pulse that acts on the seal.

A primary objective of the invention is to provide a process for applying container seals (closures or caps) of magnetic field responsive material by deforming or shaping them, characterized by subjecting them to an electromagnetic pulse that acts on the seal.

Another objective of the invention is to provide a process for applying container seals (closures or caps) of metal characterized in that they are shaped by an electromagnetic pulse that acts on the rim of the seal.

Another objective of the invention is to provide a process for shaping container seals (closures or caps) characterized in that a deforming electromagnetic pulse is generated with a current coil by way of the discharge current of a capacitor.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that the discharge of the capacitor takes place aperiodically, periodically, or as a sine half-wave.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that it consists of a pulse coil and a pulse generator.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that the pulse coil tightly surrounds the rim of the closure.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that the pulse coil is connected via a pulse transformer to the pulse generator.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that a back stop or brace for the top of the closure is connected to the pulse coil assembly.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized in that the closure to be deformed is located in the homogeneous part of the coil field.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized for closing milk and milk products and beverage containers.

Another objective of the invention is to provide a process for deforming container seals (closures or caps) characterized by a conical tapering starting from the opening.

The problem set forth in "BACKGROUND OF THE INVENTION" is solved according to the invention by means of an electromagnetic pulse that acts on the seal.

The process according to the invention offers the advantage that the seal--by means of the electromagnetic pulse acting upon it--is tightly shaped around the container nozzle or bottle neck, without any material friction or without any mechanical damage, so that no additional sealing means are required for a tight container seal.

It is particularly advantageous for shaping the seal when the electromagnetic pulse acts on the edge on the preferably thin-walled seal. The electromagnetic pulse is generated by means of a current coil due to the discharge current of a condenser. The condenser can be discharged aperiodically, periodically, or as a sine half-wave.

In closing containers, the seal to be shaped is preferably arranged in the approximately homogenous part of the magnetic field of a current coil.

An instrument to perform the process according to the invention is characterized in that it consists of a current pulse coil and a pulse generator. The current pulse coil envelopes the edge of the seal to be shaped tightly. It is connected to the post generator, if necessary, via a pulse transformer.

There is a danger--especially when one uses thin aluminum foils or foils made up of a light-metal alloy--that the seal, upon closing, will be made to bulge upward in its middle part as a result of the electromagnetic pulse. This can be prevented in a simple manner in that the current pulse coil is connected with a brace for the seal that best consist of copper.

A particularly tight and reliable pull of the seal on the container opening furthermore can be attained by inserting the container, with a conical taper of the edge or the container neck from the container opening, to apply the process according to the invention.

The diagrams illustrate preferred practical examples of the invention.

FIG. 1 is a profile through a beverage bottle or a container for dairy products or the like with a seal placed upon the bottle neck but not yet shaped;

FIG. 2 is a profile through the beverage bottle or the container in FIG. 1, with an electromagnetic pulse coil that surrounds the seal that is loosely placed on the container;

FIG. 3 shows the tightly-closing seal shaped upon the container neck, after a high electromagnetic pulse has acted on the seal from the pulse coil;

FIG. 4 is a lateral profile through the pulse coil with the course of the magnetic field line, indicated by arrows;

FIG. 5 illustrates the electromagnetic pulse in the form of a current-time diagram;

FIG. 6 is a profile through a beverage bottle or a similar container with a coil holder and pressure plate placed upon the bottle or container neck.

FIG. 7 is a pictorial illustration of the essential parts of a mechanism for the simultaneous closing of several milk or beverage bottles moving, one behind the other, on a transport device; and

FIG. 8 is a pictorial illustration of a transport device with a device--arranged over it--for the simultaneous closing of several milk bottles or the like that stand next to each other in transport crates.

FIG. 9 is a profile through a beverage bottle or a similar container with a coil holder and heat exchange pressure plate using a liquid heat exchange medium placed upon the bottle or container neck.

FIG. 10 is a profile through a beverage bottle or a similar container with a coil holder and heat exchange pressure plate using air as the heat exchange medium placed upon the bottle or container neck.

FIG. 1 shows a container or a beverage bottle 1 with a container edge or container neck 2 that reveals one or several grooves 3 to receive a shaped seal (closure or cap) 4. Seal 4 has a cylindrical edge 4a and is not in shaped in FIG. 1.

In FIG. 2, seal 4, loosely placed on the container or beverage bottle 1, is surrounded by an electromagnetic current pulse coil 5.

FIG. 3 shows the tightly closing seal 4 that is shaped upon container edge or container neck 2, after a high electromagnetic pulse has acted on seal 4 from the current pulse coil.

FIG. 4 is a current pulse coil 5 that has a passage opening 6, corresponding to the shape of container neck 2. It can be round or also rectangular or polygonal.

The electromagnetic pulse can be transmitted aperiodically or periodically or also as a sine wave.

The electromagnetic pulse is generated by the rapid discharge of an electrical condenser. Pulse induces a high current in seal 4 and that current seeks to bypass the magnetic field of the pulse and thus exerts a radial force on edge 4a of seal 4 that leads to the shaping of the edge.

A force is also exerted on the bottom of seal 4 during the pulse. FIG. 6 shows how this force can be intercepted by a pressure plate or brace holder 8 that, for example, is connected with a coil holder 7 and best consists of copper or aluminum, in order to shape the magnetic field by means of the eddy current formation (skin effect).

The operation may be enhanced by heating and/or cooling the pressure plate with a heat exchanger 21 as illustrated in FIG. 9. In this embodiment, a liquid heat transfer fluid flow toward the pressure plate through the inner tube 23 and returns to its source via the surrounding chamber 24.

In the embodiment illustrated in FIG. 10, the heat exchange is accomplished by a heat sink 24 fabricated from a material such as copper with heat exchange fins 25 extending into a flowing air stream.

In the practical example shown in FIG. 6, the container edge or container neck 2 is slightly conical, illustrated as tapering from the container opening; this causes a particularly tight seal if the initially cylindrical edge 4a of seal 4 is shaped and comes to rest tightly against the bottle or container neck 2.

The process and equipment to perform the process according to the invention are particularly suitable for sealing the lids or seals 4 that are made of light metal such as aluminum and other electrically conducting metals or magnetic field responsive materials and that are used on containers for milk and dairy products and other beverages.

Two such devices are shown in FIGS. 7 and 8; FIG. 7, milk bottles 10, with loosely placed seals 4, arrive standing one behind the other on a conveyor belt 11 and several of them, at one time, are closed up simultaneously by a shaping device 12.

Shaping device 12 can be moved up and down in the direction of double arrow 13 and has several current pulse coils 5 arranged in series behind each other. After lowering upon container or bottle necks 2, it is moved along, with conveyor belt 11, for each shaping step, in order then, in accordance with the motion diagram 14, once again to be moved back into the starting position to close up the following bottles. The shaping here is always done in area 15 of this motion diagram.

This also applies to the illustration in FIG. 8, for several milk bottles 10 stand next to each other in transport crates 16 and, via conveyor belt 11, are moved under dispenser 7 which is arranged for several seals 4, each time; all of them are then simultaneously closed up in the manner described by the shaping device 12.

While preferred embodiments of this invention have been illustrated and described, variations and modifications may be apparent to those skilled in the art. Therefore, we do not wish to be limited thereto and ask that the scope and breadth of this invention be determined from the claims which follow rather than the above description.