DE2404197A1 - Prepared lid placing system on container - uses thin lid held against container edge during securing operation - Google Patents

Abstract

The lid is applied to the prepared edge of the container and glued, sealed or welded in position by heat and/or pressure. The lid is of a relatively thin material, and is held against the edge of the container before and during the securing operation. The lid can be held so taut that it cannot be damaged, e.g. by the applied vacuum, and a closing head can be used, having a holding device on the inside, and a securing mechanism on the outside. The holding device may be in the form of a plate, with drillings in it, connected to a source of air or gas, while the securing mechanism can consists of a circular die covering the container edge, and heated. Pressure of the die against the edge can be adjustable, e.g. by a compression spring.

Description

Method for attaching prepared lids to containers and device for performing the method ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ z ~~~~ ~~~ j ~~~~~~~~~~~~~~~~~~~~~~~~~.

The invention relates to a method for attaching prepared Lids on containers, with the lid placed on the prepared edge of the container and then under the action of heat and / or pressure by gluing, sealing or welding attached to it and a device for performing this process.

Known methods of this type have the disadvantage that the cover a must have a certain rigidity and thus strength so that they are in their position in Can be locked in relation to the container opening. This lock is required to prevent the lid from moving in relation to the container opening before and during the closing process does not move.

Attempts to use containers with very thin lids, e.g. for packing are used by chocolate, etc., to seal, did not lead to success, because such very thin lids deformed so that a perfect closure was not possible. The locking mechanism also often had damage to the surface of the lid, making it unusable for food packaging in particular because bacteria or dirt or the like hes accumulate in the damage could.

The object of the invention is to avoid these disadvantages and that To conduct the procedure and to train the device for the execution of the procedure in such a way that that it is possible to use very thin foils as a cover. This becomes material saved, which is very important especially with plastic lids. The so far Foils used as lids had to have a minimum thickness of 0.055 mm so they could still be processed satisfactorily. After this procedure According to the invention it is possible to produce films with a minimum thickness of 0.002 mm to use.

Another object of the invention is also in use These very thin foils close as many containers as possible in a short time can without sacrificing processing capabilities, after all it is An object of the invention, the device for performing the method very compact and thus to save space and material.

The problem on which the invention is based is achieved in that the relatively thin laid-on cover before and during attachment is held on the edge of the container.

With this measure, a completely new path is broken. It a specially arranged holding device ensures that that the cover, which is much too thin, can no longer deform. Only after the At the end of the fastening process, the holding device is removed or ineffective made.

One way to hold the lid is to make it non-destructive, e.g. by negative pressure, held taut will. If you use negative pressure for holding the lid, you have the advantage of being able to vary the Adhesive force between the lid and the device. By equalizing the negative pressure the adhesive force to zero when the fastening process is finished #, one sets in apply a slight overpressure to the same system after the fastening process has been completed a, the cover is removed from the holding device and thus the effect achieved a stripping device.

More options that are particularly useful when using very Offer thin foils, consist in that the lid is non-destructive with formation is held by stretch wrinkles. Such expansion folds are useful when getting after closing the container by any influences, e.g. by cooling or gas formation, pressure shields between the interior of the container and the atmosphere to adjust. The expansion folds then allow a change in volume of the interior of the container to, whereby the pressure differences are reduced.

A preferred device for performing the method according to Invention consists in the fact that a locking head is present, the inside holding devices and has external fastening devices.

With this measure you can save a lot of space Single devices side by side because the holding device is inside the fastening device is arranged, in contrast to known arrangements in which locking devices lie outside the fastening device and thereby a considerably larger one Take up space. The fastening device corresponds to the edge of the container designed in the shape of a circular ring and acts on the cover in its area.

With regard to the holding device, there is a preferred embodiment in that this is a plate which has bores in the region of the container opening which are connected to a conduit carrying a gaseous medium, e.g. Air, leads, The pressure in the line is controlled so that when the Lid on the edge of the container and there is negative pressure during the fastening process, to hold the lid in place. After completing the fastening process the line receives a slight overpressure, which removes the cover from the holding device Will get removed.

These devices work so gently that even when used There is no risk of damage from the thinnest foils, especially if the Fastening device a circular ring-shaped, the container edge covering, heated The stamp is the pressure applied to the container edge by means of a Compression spring is adjustable. In the event that the cover sections with the Container is to be connected, it is essential that the annular heating surface of the stamp is heated in sections. one achieves so that the lid in a first station is first stapled and in a next station completely tight is welded. A similar effect can be achieved by attaching cams to the circular heating surface can be achieved 0 An increase in the connection surface between the lid and the container is achieved in that the annular heating surface has a circumferential projection0 This circumferential projection welds the Lid not only with the container edge, but also with a suitable depth the cylindrical inner surface adjoining the container edge. Using With certain plastic foils, it is possible to use pulse heating for the stamp to provide.

However, it is not just plastic films, but also plastic Laminated metal foils, paper coated with constituents, lacquer-coated aluminum foils and the like. Processable.

An embodiment of the invention is shown in the drawing, from its description further features of the Invention emerge, There are: FIG. 1 a device for carrying out the method in longitudinal section in FIG open position; FIG. 2 shows a section of the device according to FIG. 1 in the working position and FIG. 3 shows a partial section of the device similar to FIG. 2, but in a different form Working position, in the drawing is the lid 1 and in a receptacle 2 is the container 3 shown. This has a container edge 4 which is prepared accordingly. The zone 5 opposite the container edge 4 is also prepared on the lid 1, this preparation also extending over the entire underside of the cover 1 can. The entire device is referred to as the closing head 6. This is from a holding device 7 and a fastening device 8 are formed. In the exemplary embodiment the holding device 7 has a plate 9 in which there are narrow bores 10, These are arranged in the area of the container opening 11 and via corresponding bores connected to a line 12.

This line 12 is marked with a not shown Air reservoir in connection with which negative or positive pressure can be generated, depending on whether the cover 1 is to be held or removed from the plate 9, the holding device 7 is provided with a pin 13 which is easily axially displaceable in a sleeve 14 is guided0 At the upper end of the pin 13 is a Jech 15 attached, into which the line 12 opens, which via bores 16 in the pin 13 and 17 in the holding device 7 communicates with the bores 10 in the plate 9. The #och 15 serves the Limitation of the stroke of the holding device 7. The sleeve 14 is with the help of an intermediate piece 17 clamped in a receptacle of a circular punch 18 as the essential Part of the fastening device 8 has a circular heating surface 19, which is heated by a heating element 20. The heating element has ring channels 21, to which a supply line 22 leads. About the supply line 22 can in the ring channels 21 electrical heating resistors can be inserted, but it is also possible, depending on Need and expediency through the ring channels a gaseous or a liquid To conduct heating medium. To an undesirable and for the cover 1 under certain circumstances to avoid harmful heating of the holding device 7 with the plate 9 is between the stamp 18 and the holding device 7 a thermal insulation 23 attached, in Execution case a bell-shaped sheet metal, which the Haltevorriohtung 7 from thermal radiation, starting from the fastening device 8th, protects, the intermediate piece 17 is connected to a guide bushing 24, which is supported against a plate 26 via a compression spring 25. The plate 26 acts an adjusting screw 27 in a traverse 28, which is only partially shown, which stroke movements in the direction of arrow 29.

With the help of a flange 30, the guide bushing 24 is on the traverse 28 attached. The guide bush 24 is easy to move axially in one Block 31 stored, this storage can then, if play-free run is required is, for example, consist in ball guides, not shown.

A stop screw 32 is located on the upper side of the intermediate piece 17 intended. In the position shown in Fig. 1, the holding device is through a tension spring, not shown, between the block 31 and the yoke 15 against a resilient stop, also not shown, in block 31 in FIG In position, the cover 1 adheres to the line 12 as a result of the negative pressure of plate 9.

The distance between the cover 1 and the heating surface 19 is dimensioned so that that undesired heating, which may be associated with warping of the lid is to be avoided. Moved to apply the lid 1 on the container edge 4 the traverse 28 downwards and thus the entire closing head 6o Holding device 7 by the tension spring, not shown, in the fastening device 8 drawn in because the stop, also not shown, in block 31 is stationary remains when the guide bush 24 aware of the movement of the traverse 28 following moved down.

The closing head finally takes the position shown in FIG a, in which the connection of the lid 1 to the container edge 4 takes place. The location the holding device 7 to the fastening device 8 is thereby through the position the stop screw 32 is determined. In the setting of the stop screw according to In FIG. 2, the cover 1 rests completely flat on the container edge 4. By further Screwing in the stop screw 32 ensures that the holding device 7 is deeper lies as the fastening device 8, where a working position is established, as shown in FIG. The cover 1 is in the area of the holding device 7 is planar, but extends conically on the outside with the formation of expansion folds 33 towards the edge of the container 4, by further unscrewing the stop screw 32 achieved that the holding device is higher than in relation to the container edge the fastening device and thus also the cover in the area of the holding device protrudes over the edge of the container. In this position, the lid can be opened of negative pressure in the container after closing inwards in order to change the volume yield while he is in the position shown in Fig. 3 in order to avoid Overpressure in the container can give way to the outside.

In the illustration on the right-hand side of FIG. 3, the heating surface 19 of the stamp 18 has a circumferential projection 34 which the cover 1 in the cylindrical Inner part of the container 3 presses in and it is also welded there so that the Total connection area between the lid and the container is increased.

As already stated, the heating surface 19 can also be sectional be carried out heatable, which is not shown in the drawing, as well it can have cams not shown.

After the connection process between the edge of the container and the lid in one the positions described traverse the traverse 28 and thus the entire closing head back to the starting position shown in FIG. 1 and after application a new cover 1 on the holding device 7, the next cycle can begin.

The force with which the fastening device 8 closes the cover 1 Pressing on the container edge 4 can be adjusted by adjusting the adjusting screw 27 and can thus be adapted to the respective requirements. The compression spring 25 expediently has a flat characteristic, whereby it is achieved that Changes in length, for example as a result of temperature changes> or tolerances in the The thickness of the edge of the container and the lid is negligible The pressing force of the fastening device 8 has an effect.

As can be easily seen from the exemplary embodiment, the closing head has with respect to the diameter of the container or the container lid a minimum Diameter, so that a number of such locking heads are arranged close to one another can be used to increase the number of containers that can be closed at the same time.

Claims

Claims (12)

Claims 0 Experience for fastening prepared lids on containers, with the lid placed on the prepared edge of the container and then under the action of heat and / or pressure by gluing, sealing or Welding to be attached to it, d u r c h e k e n n n z e i c h -n e t that the relatively thin, laid-on cover (1) before and during attachment on the container edge (4) is held0 2. The method according to claim T, d a d u r c h 9 e k e n n -z e i c h n e t that the cover (1) is destructive, z0B. is held taut by negative pressure. 3. The method according to claims 1 and 2, d a d u r c h g e k e n It is noted that the cover (4) is non-destructive with the formation of expansion folds (33) is held. 4. Device for performing the method according to claims 1 to 3, d a d u r c h 9 e k e n n z e i c h -n e t that a closing head (6) is available is, the inside a 'holding device (7) and outside a fastening device (8) owns. 5. Apparatus according to claim 4, d a d u r c h g e k e n n z e i c h n e t that the holding device is a plate (9) which is located in the region of the container opening Has bores (10), which is connected to a line (# 2), which is a gaseous Medium, e.g. air, 6 Device according to claims 4 and 5, d a d u r c it should be noted that the fastening device is an annular2 the heated plunger (18) covering the edge of the container (4) is 0 7. Device according to claims 4 to 6, d a d u r G h e k e n n z e i c h n e t a that the contact pressure of the stamp (18) on the container edge (4), e.g. by means of a compression spring (25), adjustable is, 8. Apparatus according to claim 6, d a d u r c h g e k e n n z e i c h n e t s that the annular heating surface (19) of the punch (18) can be heated in sections is. 9. Device according to claims 6 and 8, d a d u r c h g e k e It should be noted that the annular heating surface (Ig) has cams. 10. Device according to claims 6 to 9, d a d u r c h g ek e It is noted that the heating surface (19) has a circumferential projection (34). 11 ¢ Device according to claims 6 to 10, d a d u r c h g e k It is noted that the stamp (18) has a pulse heater, 12. Device according to claim 4 and one or more of claims 5 to 11, d a d u r c h g e k e n n -z e i c h n e t that holding device (7) and fastening device (8) are arranged concentrically to one another and there is thermal insulation between the two (23) is located,