The invention relates to a method for manufacturing tear-off lids, a device for manufacturing tear-off lids, in particular according to the method, a punching processing station for the device, and a tear-off lid manufactured or producible by the method according to the preambles of the independent claims.
Tear-off lids (so called-peel off ends or POE) are known, e.g. from DE-U 298 17 592 or from DE-U 92 03 953.
With reference to
The conveyor 13, which conveys the lid blanks, the lid rings and the tear-off lids in the manufacturing device 10 along the transport path in the direction of arrow A from one processing station to the next processing station, is formed in particular by two parallel running toothed belts, on which holders for the lid blanks or lid rings are provided, as the skilled person knows from WO 2006/017953. This will not be explained further here either. At the respective state-of-the-art processing stations, which are known to the skilled person and are only shown schematically here, the blank or ring to be processed is lifted off the conveyor, processed by the processing station and returned to the conveyor. This is indicated at the processing stations by arrows pointing up and down. In the case of the processing stations, the drive of the processing stations is indicated below the conveyor. This serves to lift and lower the blanks and lid rings and to carry out the respective processing steps.
In a punching processing station 14, a lid ring 8 is first formed from the lid blank 9 by punching a central part 16 of the blank downwards and disposing of it as waste (see
The previous manufacturing steps were carried out in a position in which the lid blanks 9 and lid rings 8 were arranged with their later top side or with the sealing flange 18 pointing downwards. This is a preferred embodiment also for the present invention. As mentioned above, the blank 9 or the ring 8 is lifted off the conveyor 13 in the individual processing stations 14, 19 and 21, processed and put back again, whereupon the conveyor carries out conveying steps, which lead the lid blanks 9 or lid rings 8 to the next processing station. If the manufacturing steps are carried out with the sealing flange 18 pointing downwards, as shown in the figure, a turning station 23 follows, which turns the lid rings 8, so that during further processing the sealing flange 18 is at the top after the turning station 23 in the conveyor 13 and in the processing stations 25, 26.
Then the tear-off foil 24 is sealed onto the sealing flange 18, which can be done in two steps with a pre-sealing station 25 and a main sealing station 26. The sealing method is also known to the skilled person and will not be explained further here. Further processing stations may follow in which the sealing foil 24 is embossed, the tear-off tab 15 is positioned and a leak test is performed. This is also known to the skilled person and will not be further explained here. At the end of the known manufacturing device 10, finished tear-off lids 27 are issued (see
With the state-of-the-art system described above, a punching or cutting pad is produced on the intended outside (underside) of the lid ring produced during punching of the lid blank, which is particularly suboptimal if a “reverse curl” (rolling up away from the removal opening) is subsequently produced. In this case, it would be desirable from a production point of view if the (unavoidable) punching or cutting pad would be produced on the intended inside (top side) of the produced lid ring, with otherwise unchanged method sequence or system concept.
The invention has the objective of providing technical solutions by means of which the previously described known and established methods and devices for the production of tear-off lids can be modified with the least possible technical effort so that the punching or cutting pad is produced on the other side of the lid with essentially unchanged method sequence and system concept.
This objective is reached by the method, the device and the punching processing station according to the independent patent claims.
According to these claims, a first aspect of the invention concerns a method for manufacturing a tear-off lid. In this method, a lid blank is punched with a punching tool to form a lid ring with a central removal opening, which is surrounded by a sealing flange. The punching tool has a die and a cutting punch.
The edge of the removal opening is then shaped by drawing to form a collar which protrudes from the sealing flange on the side forming the inside of the lid (intended inside of the lid) when the lid is later used for the intended purpose.
The collar is then rolled up at its free end and then a tear-off film is sealed or glued onto the sealing flange on the side forming the outside of the lid (intended outside of the lid) during the later intended use of the lid to be produced.
According to the invention, during punching the die is placed on the side of the lid to be produced that forms the inner side of the lid during the later intended use (intended inner side of the lid), and the cutting punch is moved into the die from the side of the lid to be produced that forms the outer side of the lid during the later intended use (intended outer side of the lid) while a punched pad is being punched out.
The punched pad produced in this way is conveyed by compressed air through the die to a conveyor, by means of which it is removed from the tool area.
The invention makes it possible to modify the currently known and established methods and devices for the production of tear-off lids with very little effort in such a way that, with essentially unchanged method sequence and system concept, the punching or cutting pad is produced on the side forming the outside of the lid (intended outside of the lid) when the lid to be produced is later used in accordance with the intended purpose.
In a preferred embodiment of the method, a lid blank is used, which consists of a ferromagnetic material. A magnetic conveyor belt is used as a conveyor for removing the punched pad from the tool area. This allows a reliable handling and removal of the punched pad in the smallest space and with a minimum of moving parts.
In another preferred embodiment of the method, a vacuum conveyor belt is used as a conveyor for removing the punched pad from the tool area. This also allows a reliable handling and removal of the punched pad in the smallest space and with a minimum of moving parts and ferromagnetic as well as non-ferromagnetic lid blanks, e.g. of aluminium, can be processed.
Magnetic and vacuum conveyor belts are generally known in the field of conveyor technology and therefore need not be explained in detail here.
The compressed air, which is used to convey the punched pad to the conveyor, is advantageously fed through the cutting punch.
It is preferable that the compressed air that is led through the cutting punch is brought to the outlet on the side of the cutting punch facing the lid blank or the punched pad via one or more outlet openings. In this way, air can be applied directly to the side of the punching butt facing the cutting punch and thus reliably guided away from it.
It is advantageous that the compressed air, which is led through the cutting punch, is discharged on the side of the cutting punch facing the lid blank or the punched pad via three identical discharge openings, which have identical distances to each other. Such a configuration of the outlet openings effectively prevents the punched pad from skewing or tilting in the die.
Furthermore, in the embodiments of the method in which the compressed air passed through the cutting punch is discharged via one or more outlet openings on the side of the punch facing the lid blank or the punched pad, it is preferred that this compressed air, which is used to convey the punched pad to the conveyor, is provided intermittently. The advantage of this is that no compressed air is supplied when the tool is open and compressed air is supplied when the tool is closed. This simplifies the process control and saves energy as compared to a permanent supply.
It is also preferred that the compressed air is applied to the outlet openings only at the beginning of the punching process or, even more preferred, only after the punching process has been completed, preferably after the end of the movement of the cutting punch, which is the top dead center of the movement of the cutting punch in the case of cutting punches working upwards.
In the latter case, the punched pad is completely separated from the cover blank before compressed air is applied, which has the advantage that a cleanly controllable process sequence is possible.
In a first preferred variant of the method according to the invention, the collar, which is formed from the edge of the removal opening by drawing, is rolled up towards the removal opening, to form a C-Curl or a Retort-Curl.
In a second preferred variant of the method according to the invention, the collar formed from the edge of the removal opening by drawing is rolled up away from the removal opening into a reverse C-curl or a reverse retort curl. In this second variant, the advantages of the invention are particularly evident.
Furthermore, in the method according to the invention it is preferred that the cutting punch is moved and the die is stationary during punching, that the cutting punch penetrates the die from the bottom to the top during cutting and/or that the lid ring is turned between the rolling up of the collar and the sealing or gluing of the tear-off foil. This makes it possible to use today's known and established production systems with minor modifications at the punching processing station to carry out the method. An appropriate die-cutting processing station according to the invention is the subject of the third aspect of the invention, which will be explained later.
Preferably, after punching the lid ring is conveyed out of the cutting tool in a first transport direction and the punched pad is removed from the tool area by the conveyor in a second transport direction, which is transverse to the first transport direction, in particular perpendicular to the first transport direction. This has the advantage that the punched pad can be removed with the conveyor directly into the area in front or behind the production system.
A second aspect of the invention relates to a device for the production of tear-off lids, in which a tear-off foil is sealed or glued on the upper side of the lid on a sealing surface arranged around a removal opening. Preferably, the device is adapted for the production of tear-off lids according to the method of the first aspect of the invention.
The device comprises a first conveyor for lid blanks, lid rings and tear-off lids as well as processing stations, which are provided in succession in the conveying direction for processing the lid blanks, lid rings and tear-off lids. A first processing station is designed as a punching processing station for forming a lid ring with a central removal opening surrounded by a sealing flange from a lid blank by punching it with a punching tool comprising a die and a cutting punch. A second processing station of the device is adapted to form a collar protruding from the lid ring, a third processing station to roll the collar into a curl and a fourth processing station to seal or glue a tear-off foil onto the sealing flange. Such a device was described in the introduction using
In accordance with the invention, the first processing station is designed in such a way that during punching the die is arranged on the side of the lid to be produced that forms the inner side of the lid during the later intended use (intended inner side of the lid) and the cutting punch is arranged from the other side, thus from the side of the lid to be produced that forms the outer side of the lid during the later intended use (intended outer side of the lid), and is inserted into the die by punching out a punched pad. Devices are provided for conveying the punched pad by means of compressed air through the die to a second conveyor assigned to the first processing station, by means of which the punched pad is removed from the tool area during intended operation of the device.
Such devices for the production of tear-off lids have the advantages already mentioned in the method description and can be built from existing systems with very little modification, while the method sequence and system concept remain unchanged.
The second conveyor is preferably a magnetic conveyor belt or a vacuum conveyor belt, by means of which the punched pads can be removed from the tool area.
The cutting punch has advantageously one or more air ducts to transport the compressed air within it, which is used in the intended operation to convey the punched pad by means of compressed air through the die to the second conveyor.
For this purpose, the cutting punch has one or more outlet openings for the compressed air on its side facing the cover blank or the punched pad. In this way, the punched pad can be supplied with compressed air directly on its side facing the cutting punch and thus be reliably guided away from it to the second conveyor.
It is especially preferred if the cutting punch has several, e.g. three, especially identical outlet openings, which have identical distances to each other. Such a configuration of the outlet openings can effectively prevent the punched pad from tilting in the die.
Furthermore, it is preferable that the device has a control system by means of which, in intended operation, the compressed air used for conveying the punched pad to the second conveyor can be or is intermittently provided, preferably in such a way that no compressed air is provided when the tool is open and compressed air is provided when the tool is closed, in particular from the point when the end of movement of the cutting punch is reached. This simplifies the method control and saves energy.
In a first preferred variant of the device according to the invention, the third processing station is designed in such a way that the collar, which is formed from the edge of the removal opening by drawing, is rolled up towards the removal opening, to form a C-curl or a retort-curl.
In a second preferred variant of the device according to the invention, the third processing station is designed in such a way that the collar formed from the edge of the removal opening by drawing is rolled up away from the removal opening, to a reverse C-curl or to a reverse retort curl. The advantages of the invention are particularly evident in this second variant.
Furthermore, it is preferred that the device according to the invention is designed in such a way that the cutting punch is moved and the die is stationary during punching, that the cutting punch penetrates into the die from bottom to top during cutting and/or that the lid ring is turned in a turning station between the rolling up of the collar and the sealing or gluing of the tear-off foil. This makes it possible to convert today's known and established production lines with a slight modification of the punch processing station into a device in accordance with the invention. An appropriate punch processing station according to the invention is the subject of the third aspect of the invention, which will be explained later.
Preferably, the first conveyor has a first transport direction and the second conveyor has a second transport direction, which is transverse to the first transport direction, preferably perpendicular to the first transport direction. This has the advantage that the punched pads can be transported directly to the area in front of or behind the production line.
A third aspect of the invention concerns a punching processing station for a device according to the second aspect of the invention, for forming a lid ring with a central removal opening surrounded by a sealing flange from a lid blank by punching.
The punching processing station comprises a punching tool with a fixed die and a cutting punch, which, in the intended punching operation, works from below against the die and thereby moves into the die while punching out a punched pad.
In addition, it comprises devices for conveying the punched pad in the intended punching operation by means of compressed air against gravity through the die to a conveyor associated with the punching processing station, for removing the punched pad from the tool area.
Such punching processing stations can be used to convert production systems known and established today as described above into devices in accordance with the second aspect of the invention.
A fourth aspect of the invention concerns a tear-off lid manufactured or producible with the method according to the first aspect of the invention. Such tear-off lids represent an important trading form of the invention.
Further embodiments, advantages and applications of the invention result from the dependent claims and from the following description of the figures. Thereby it is shown in:
In the introduction, the production of tear-off lids 27 according to the state of the art, as known to the skilled person, is explained with reference to
In the following, the procedure according to the invention is described, whereby reference is made to the known device and the known, previously explained manufacturing steps, as far as this is necessary. In particular, the device and the method according to the invention for forming the lid ring 8 from the lid blank 9 and for sealing the tear-off foil 24 are also proceeded as already known to the skilled person.
As can be seen, the tool comprises an upper tool part 1, with a cutting punch 2, 3 comprising a cutting ring 2 and a cutting ring carrier 3 and with a clamping ring 4, and a lower tool part 5, with a die 6 and a die carrier 7.
The upper tool part 1 with the cutting punch 2, 3 is fixed and the lower tool part 5 with the die 6 works against the upper tool part 1.
In the tool position shown in
Starting from this situation, a lid blank 9 is inserted into the tool in a horizontal direction with the conveyor 13 (see
The lower tool part 5 is then moved upwards until the lid blank 9 is clamped between the clamping ring 4 and the die carrier 7 (see
During the subsequent further upward movement of the lower tool part 5, the clamping ring 4 is shifted upwards against the force of compression springs 29, which are arranged in the upper tool part 1, and the cutting punch 2, 3 penetrates the die 6 (see
When the die 6 has reached its movement end point relative to the cutting punch 2, 3 as shown in
As can be seen, the tool here also comprises a fixed upper tool part 1 and a lower tool part 5, which works against the upper tool part. In contrast to the punch processing station 14 according to
The lower tool part 5 has a cutting punch 2, 3 comprising a cutting ring 2 and a cutting ring carrier 3, as well as a clamping ring 4. As can be seen, the cutting ring carrier 3 has internal air ducts 34, which open into several outlet openings 35 located on the upper side of the cutting punch 2, 3.
In the tool position shown in
Starting from this situation, a lid blank 9 is inserted into the tool in a horizontal direction with the conveyor 13 (see
The lower tool part 5 is then moved upwards until the lid blank 9 is clamped between the clamping ring 4 and the die 6 (see
During the subsequent further upward movement of the lower tool part 5, the cutting punch 2 moves out of the clamping ring 4, which is in contact with the clamped lid blank 9 at the die 6, and enters the die 6. It punches a punched pad 16 out of the lid blank 9 (see
As soon as the cutting punch 2 has reached its end point of movement opposite the die 6, i.e. it is at the top dead center of its movement, as shown in
The lower tool part then moves back to the lower position shown in
While the present application describes preferred embodiments of the invention, it should be clearly pointed out that the invention is not limited thereto and can also be implemented in other ways within the scope of the following claims.
Number | Date | Country | Kind |
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01478/19 | Nov 2019 | CH | national |
This application is a National Stage application of International Patent Application No. PCT/EP2020/082266, filed Nov. 16, 2020, which claims the priority of Swiss patent application 01478/19, filed Nov. 22, 2019, the disclosure of which is incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/082266 | 11/16/2020 | WO |