CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority of Swiss patent application 0531/10, filed Apr. 13, 2010 and PCT Application No. PCT/CH2011/000071, filed on Apr. 4, 2011, the disclosures of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The invention is related to an arrangement for forming a band loop between a delivery spool which is actuated in an uncoiling manner and a band drawing-in device. Particularly, the arrangement is used for a method to produce peel-off lids, comprising the forming of a plurality of parallel rows of lid rings made of metal, wherein a stepwise transport of the lid parts to a plurality of processing stations and a stepwise delivery of a foil band from a delivery spool to the lid rings and the stamping out of foil sections as well as the appliance and heat sealing of the foil sections onto the lid rings in a stamping and sealing processing station are carried out, wherein a foil band loop, which comes to lie between the foil band spool and the drawing-in of the foil band into the stamping and sealing processing station, is formed in the foil band by means of the arrangement. Furthermore, the invention is related to a device for manufacturing peel-off lids with an arrangement according to the invention.
BACKGROUND
It is known how to execute lids for can-like or tin-like packaging as metal lids permanently attached on the top of the packaging, having an extraction opening remains closed until the first usage of the packaging contents by means of a peelable foil attached by heat sealing, particularly a metal foil. An additional lid made of plastic and arranged on top of the metal lid makes it possible to close again the packaging during the consumption period of the contents. Devices for manufacturing such metal lids will be explainer in the following in more detail by means of FIG. 5. FIGS. 6 to 12 serve to explain manufacturing steps during the production of such lids. The peelable foil is drawn off a band delivery spool as a wide foil web and is inserted into the stamping and sealing stations or it is guided over the lid parts respectively. In order to provide a band delivery for the drawing-in of the foil band into the stamping and heat sealing processing station, one or more so-called dancer roll systems are used, which may however result in problems regarding the stepwise foil transport in the presence of high manufacturing cadences, particularly also in case of thin foil bands. Band loops of the ordinary type are generated by the controller of the actuator of the uncoiling delivery spool and are regulated by e.g. a distance sensor which measures the distance from the stationary sensor. For strongly changing drawing-in lengths in the presence of a high band speed, this is complex with respect to the actuation or it yields insufficient results. In DE-A 40 02 194 the forming of a band loop by means of an air current is proposed.
It is the objective of the invention to provide an arrangement by means of which a band loop can be provided in a simple way and which works in a reliable way in the presence of high manufacturing cadences with a stepwise band transport and in case of the most different foil materials.
This objective is reached by the present invention.
SUMMARY OF THE INVENTION
It has been noticed that, by the hollow cylinder which is freely movable within certain limits, which consequently lies loose on the band for some time and forms the lower deflection of the band loop, a stable band loop is reached even under said conditions. In this way also plastic foils or laminate foils or aluminium foils with band speeds of 60 meters/minute and drawing-in lifts of 50 to 150 millimeters per lift can be handled very well, thus enabling the usage of the arrangement during the manufacturing of peel-off lids with high cadence.
Preferably, a transversal bar lying horizontally and supported on both sides in the side walls runs through the hollow cylinder and limits the free mobility of the hollow cylinder. This results in a particularly easy path limitation for the hollow cylinder. Furthermore it is preferred that the transversal bar is arranged in a vertically shiftable way in a vertical groove guidance in the side walls in order to limit the mobility of the hollow cylinder in vertical direction. The diameter and also the material of the hollow cylinder can be differently chosen. The diameter can be chosen to be e.g. 20 cm or larger. Particularly plastic is a suitable material.
Furthermore, the invention has the objective to provide a method and a device for manufacturing peel-off lids, in case of which the advantageous arrangement for reaching a band loop is used. This is accomplished by the method or the device of the present invention respectively.
The foil band is preferably supplied to the stamping and sealing processing station with partially unequal step lengths in a horizontal way and, as seen horizontally and from the top, with its longitudinal direction substantially perpendicular to the transport direction of the lid parts.
By delivering the foil web in a right angle it is possible, contrary to the ordinary oblique delivering, to save around 20% of the foil. However, the straight delivering results in a strong fluctuation of the step length of the foil band delivering in case of more than two parallel manufactured rows of lids. The stabilizing of the foil band loop by means of the arrangement makes it possible to handle the foil or large step lengths fluctuations respectively, equally in the presence of high delivering speeds.
BRIEF DESCRIPTION OF THE DRAWINGS
Further embodiments of the invention and the manufacturing of peel-off lids are described in more detail by means of the following figures.
FIG. 1 a schematic side view of an embodiment of an arrangement according to the invention in operation between a delivery spool and a band drawing-in;
FIG. 2 the arrangement of FIG. 1 with the hollow cylinder lifted from the band;
FIG. 3 the arrangement according to FIG. 1 in a perspective view;
FIG. 4 a side view of the arrangement with another position of the hollow cylinder;
FIG. 5 a schematic side view of a known device for transporting and manufacturing peel-off lids; and
FIG. 6 to FIG. 12 sectors of metal lids for explaining the manufacturing of the lids.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 to 4 show an embodiment of an arrangement 1 according to the invention. It is provided and adapted to form a band loop 7 in a band 6. The band 6 is uncoiled from a band delivery spool 2 in an actuated manner and thereafter gets into the arrangement 1. Thereafter, the band is transported by a drawing-in device 4 which belongs to a device inside which the band is used or processed respectively. An example of such a device is explained in the following. The shown band transport reveals the band transport direction D. The uncoiling from the band delivery spool is normally done with constant speed or it may be adjusted to fast speed changes of the drawing-in device 4 via the actuator 19 only comparatively slowly. Particularly, the drawing-in device 4 can cause a stepwise drawing-in of the band with changing drawing-in lengths. Thereby, the arrangement 1 has the purpose to compensate for the drawing-in fluctuations with respect to speed and/or drawing-in step lengths by means of the band loop 7, in such a way that the loop forms a band material stock which can easily be drawn in. This is basically known.
An actuator 19 which is not shown in detail is provided, being e.g. formed by an electric motor. The skilled person knows such actuators, such that no further description thereof has to be specified. The actuation 19 can be done by controlling the device with the drawing-in device 4, in order to adjust the band uncoiling to the band demand. A sensor 19′, particularly as a distance sensor, can also be provided, by means of which the actuator 19 can react to the length increase or the length decrease of the loop respectively. The sensor signals can be passed to the controller of the device and be processed there for the controlling of the actuator 19 or they may be passed to a controller which is directly attributed to the actuator, in order to supplement the controller signals from the device. The arrangement 1 has two side walls 8 and 9 which consist e.g. of plastic or metal. The band runs between these side walls and forms the loop 7 there. A hollow cylinder 10 is provided, which lies on the band and forms its deflection and therefore facilitates the loop forming and consequently determines the uncoiling reserve. The diameter of the hollow cylinder can be chosen differently. The hollow cylinder may e.g. consist of plastic, particularly polymethylacrylate (Abbreviation PMMA, common speech acrylic glass). Also, a material with a higher specific weight can be chosen in order to reach a higher pre-tension, e.g. aluminium. The hollow cylinder preferably has the shown round cross section, it could however also have an oval or polygon cross section. The hollow cylinder is substantially aligned with its end faces between the side walls, such that it can move freely between the side walls without jamming. The hollow cylinder is free in its movement to a limited extent, such that it can move freely by a certain amount in the band travel direction and perpendicular thereto. This amount depends on the diameter and on the uncoiling. The limitation of the movement can be limited by arbitrary means acting upon the hollow cylinder. Preferably, it is acted upon the hollow cylinder from the inside and particularly by means of a transversal bar 11 which is arranged lying horizontally between the side walls and extends throughout the hollow cylinder. The transversal bar 11 can be arranged in a fixed way in the side walls or it can be guided therein preferably in a vertically slidable way. For this, the shown vertical groove guidances 12, 12′ may be provided.
In FIGS. 1 and 3 the hollow cylinder 10 is shown in its vertically lowermost position. Thereby, it lies with its inner wall on the transversal bar 11 which itself lies lowermost in the groove guidances. Now, if the drawing-in device 4 pulls more band than uncoiled by the delivery spool in an actuated way, the band loop is shortened, resulting in a deflection of the hollow cylinder from the shown lowermost position. Thereby it is free with respect to its movement between the side walls. It has been noticed that even very thin and light foil bands can be handled very well as loops by means of such a freely movable hollow cylinder which, consequently, within the limits of the free movement, lies on the band only with its weight (which can be adjusted by the diameter and/or material choice of the hollow cylinder) and forms its deflection and causes the pre-tension of the band. The free movement of the hollow cylinder through the band is however limited, in the shown example by the transversal bar 11. If the way length of the free movement is used up (which in this case results by the inner diameter of the hollow cylinder) the hollow cylinder first contacts the transversal bar 11 in this embodiment, such that its free movement upwards is used up and is reduced also sideways. This position is shown in FIG. 3. Further, if more band is drawn in than uncoiled, the hollow cylinder pulls the transversal bar upwards. This is well illustrated in FIG. 4. There, a position is shown, in which more band has been drawn in by the drawing-in device during a certain time period than it has been supplied by the band delivery spool, such that the loop 7 has been shortened to such an extent that the hollow cylinder 10 has been pushed upwards and has also moved the transversal bar 11 upwards in its groove guidances 12, 12′. The upper end of the groove guidances 12, 12′ would also limit this upward movement. If thereafter the drawing-in device draws less band than supplied by the delivery spool, or if the actuation of the delivery spool is adjusted in a controlled or regulated way in such a way that more band per time unit is uncoiled, the loop 7 extends again and the hollow cylinder lying on the band moves downwards again, maximally in the position of FIGS. 1 and 2. A further extension of the loop should be avoided by the controller of the actuator of the delivery spool 2, because the band or the loop 7 respectively, should not run through the arrangement 1 without the stabilizing effect of the hollow cylinder.
In the shown embodiments the arrangement has an upper drawing-in-sided band deflector 14 and an upper exit-sided band deflector 15. The band deflectors are arranged at the upper side of the side walls. The deflectors can be rolls which rotate with the band. However, also non-rotating deflectors may be provided. Adjustable lateral limiters are preferably provided for the band, such that the latter runs in a defined position above the band deflectors 14, 15. For this, axially shiftable and fixable thrust washers 14′ and 14″ are provided on the band deflector 14 and 15′ and 15″ on the respective band deflector 14 or 15 in the shown embodiment. These thrust washers are adjusted, after releasing their attachment, in their distance with respect to the width of the band, such that they form lateral limiters for the band.
Alternatively to the shown band guidance via the drawing-in-sided deflector 14 of the arrangement 1 the band can also be guided on the drawing-in-side above a deflector 16 (FIG. 3), such that the band runs from the delivery roll 2 under the deflector roll 16 and to the hollow cylinder 10. The arrangement 1 is preferably attached to the supports 5 or 3 respectively, for the delivery spool 2, by means of adjustable attachment means 17, 18. The adjustability makes it possible to adjust the distance of the arrangement 1, in horizontal direction, from the supports 5, 3. Now, the preferred use of the arrangement when manufacturing the peel-off lids is described. Thereby, the band which is present on the band delivery spool 2 is the peel-off foil material out of which the peel-off foil is punched out for each lid. Processing stations and manufacturing steps for manufacturing metal lids with peel-off foils according to the state of the art will be explained using FIGS. 5 to 12. Thereby, FIG. 5 shows a schematic side view of a known device 21 which has a plurality of processing stations 23 to 28 as well as a further station 29 on a machine frame 22. A transport device for the lid parts is a linear transport device according to a preferred embodiment, as known from WO2006/042426. This linear transport device is adapted to transport lid-shaped objects of the type described in the following by means of toothed belts and it is suitable for a very fast transport or lid production respectively. Opposed tappets for the lid parts are provided at the mutually opposed and synchronously moved toothed belts. The transport device serves to transport in cycles the lid parts or the lids respectively, to the individual processing stations, as explained in the following. The transport device shown in FIG. 5 transports the lid parts or the finished lids with peel-off foils in a transport direction which is indicated by the arrow C, from the input of the device at the stack 31 to the output of the device where the lids get into the trays 36 or 37 via slides. Lid parts are destacked from the stack 31 in a known way and they get into the transport device. The shown transport device has another construction than the preferred linear transport device of WO2006/042426 and is only shortly described here. Two long bars, each of which is arranged at the side of the lid parts or lids respectively, are provided, which lift up the lid parts or lids respectively, lying on trays or in the stations 23 to 29, during their own lift up, by means of the actuator, in the direction of arrow A and subsequently shift them onwards by an amount in a forward motion in the direction of arrow B (in the same direction as arrow C) by means of the crank drive. Thereafter, the bars are moved downwards in the direction of arrow A, wherein the lid parts or the lids respectively are again placed onto their lay-down position. Thereafter, the bars are moved backwards below the object lay-down positions in the direction of arrow B and anti-parallel to arrow C, whereafter the described process is repeated. Between transportations, the lid parts or the lids respectively lie on their lay-down positions or are located in the processing stations respectively and are processed there. A recurring conveying takes place after a processing step through all processing stations. FIG. 6 shows stacked metal lid blanks 120 as an example for lid parts, the way they are provided in the stack 31. These blanks 120 are for example round metal disks with a diameter of e.g. 11 cm. Evidently, other basic shapes like for example square or rectangular disks and other diameters are readily possible. The blanks 120 have already been preformed at their edge, as shown in FIG. 5, in a processing machine which is not shown. In FIG. 6 and in the subsequent figures only a sector of the whole disk is shown in order to simplify the figures. In the first processing station 23 of FIG. 5, an opening 129 is stamped into the disk by means of a stamping process with an upper and a lower tool, this being shown in FIG. 7, where the edge of the opening is denoted by 121 and the stamped out round disk by 127. This disk is disposed of as debris. The stamp processing station 23 is actuated—as it is the case for the additional processing stations—by means of an actuator 115. A pulling down of the edge 121 takes place in the processing station 24, by means of which for example the shape 122 of the edge, shown in FIG. 8, is reached. The ring-shaped lid parts 120 then reach the stamping and sealing station 25, where the peel-off foil 125 is placed above the opening of the lid 120 and attached there by means of heat sealing, this being shown in FIGS. 9 and 10. The peel-off foil 125 is preferably a laminated foil or it is an aluminium foil and it has in a known way a plastic layer on the bottom side. The required precut foil 125 is stamped out of a wide foil web in the station 25 and placed above the middle cavity of the ring shaped disk and is pressed by the sealing station at the edge of the round cavity of the part 120 under the influence of heat, such that the foil 125 is sealed tightly to the metal lid 120 by melting and subsequent cooling the plastic layer. This is known and will therefore not be explained in more detail. It may also be provided that the peel-off foil is only pre-sealed in the stamping and sealing station 25 and is thereafter sealed in an additional heat sealing station. A cooling process station 27 may possibly be provided for the cooling. The foil 125 may be provided with a stamp 124 (FIG. 11) in a processing station 28 and then the edge 122 is subsequently flanged to yield the finished edge 123. The finished lids are submitted to an inspection in an inspection station 29 comprising a leak test, which is described in the following for the peel-off foil 25 which is applied on the lid. If the foil is tightly attached to the rest of the metal lid, the lid ends up in the tray for the finished lids. If a leak is detected, the lid ends up in the waste container via the other shown slide.
By means of the mentioned linear transport device lid parts or lids respectively, can be transported with a high cadence of e.g. 200 objects per minute and with reproducible partial steps between the stations. Furthermore, a flexible concept for the large format range of the objects or the lids respectively, which can range for e.g. round lids from a diameter of 40 to 200 mm and which can also receive different rectangular formats, e.g. for ordinary fish cans. The transport device is furthermore, as a compact module, particularly designed for the multiple track configuration. In combination with such a production of lids with a high cadence, the arrangement for forming the band loop can be used in a particularly advantageous way. It can however also be used for other devices where a band loop has to be generated.
A foil band loop is generated when handling a foil band to be uncoiled from a delivery spool, which is stepwise drawn into a drawing-in device. In order for this to take place in an error-free way in case of high manufacturing cadences, an arrangement is provided, in case of which a hollow cylinder for forming the band loop lies loosely on the band with limited mobility. Such an arrangement is preferably provided for manufacturing peel-off lids, in case of which a foil band is uncoiled from a band delivery spool and is provided to a stamping and sealing station.
Patent Application
20130028685
