U.S. patent application number 11/908817 was filed with the patent office on 2008-09-18 for tear-off lid and method for its manufacture.
This patent application is currently assigned to Soudronic AG. Invention is credited to Marcel Oberholzer.
Application Number | 20080223856 11/908817 |
Document ID | / |
Family ID | 36297215 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080223856 |
Kind Code |
A1 |
Oberholzer; Marcel |
September 18, 2008 |
Tear-Off Lid and Method For Its Manufacture
Abstract
The invention relates to a lid ring (20') for production of a
tear-off lid, whereby a hot-sealing coating (62) is only applied to
the edge (68) of the dispensing opening (25). A material saving is
thus possible relative to conventional full-surface application. A
coating different from the hot-sealing coating can form the lid
ring surface outside the hot-sealing coating.
Inventors: |
Oberholzer; Marcel;
(Kindhausen, CH) |
Correspondence
Address: |
MCCORMICK, PAULDING & HUBER LLP
CITY PLACE II, 185 ASYLUM STREET
HARTFORD
CT
06103
US
|
Assignee: |
Soudronic AG
Bergdietikon
CH
|
Family ID: |
36297215 |
Appl. No.: |
11/908817 |
Filed: |
March 13, 2006 |
PCT Filed: |
March 13, 2006 |
PCT NO: |
PCT/CH2006/000146 |
371 Date: |
October 4, 2007 |
Current U.S.
Class: |
220/359.1 ;
53/478 |
Current CPC
Class: |
B65D 2517/0082 20130101;
B65D 2517/0013 20130101; B65D 2517/0061 20130101; B65D 2517/5013
20130101; B21D 51/38 20130101; B65D 2517/5029 20130101; B65D
2517/5035 20130101; B65D 17/502 20130101; B65D 2517/5054 20130101;
B65D 2517/5083 20130101 |
Class at
Publication: |
220/359.1 ;
53/478 |
International
Class: |
B65D 41/32 20060101
B65D041/32; B65B 51/10 20060101 B65B051/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2005 |
CH |
453/05 |
Claims
1. Tear-off lid having a lid ring (20') with a take out opening
(25) covered by a tear-off foil (25''), wherein said lid ring and
said tear-off foil are releasable connected to each other with a
heat sealable coating (62) along the border (68) of said take out
opening by a connection area, characterized in that said lid ring
is not coated or is coated with a plastic coating different from
said heat sealable coating (62) outside of said border or said
connection area.
2. Tear-off lid according to claim 1, characterized in that the
heat sealable plastic coating is a polypropylene coating or a
coating containing polypropylene, and in particular a polypropylene
containing lacquer coating.
3. Tear-off lid according to claim 1, characterized in that the
plastic coating different from the heat sealable coating is a
polyethylene terephthalate coating or a coating containing
polyethylene terephthalate.
4. Tear-off lid according to claim 1 characterized in that the
plastic coating different than the heat sealable coating extends on
one side or on both sides over the whole lid ring and therefore
lies in the connection area beneath the heat sealable coating.
5. Tear-off lid according to claim 1, characterized in that the lid
ring comprises a flanged edge (67) beaded towards the take out
opening (25') and that the flange is covered by the heat sealable
coating.
6. Tear-off lid according to claim 1, characterized in that the lid
ring is made of metal.
7. Tear-off lid according to claim 1, characterized in that the lid
ring or the take out opening is round or oval or rectangular or is
provided with another non round shape.
8. Container with a tear-off lid according to claim 1.
9. A method for manufacturing a tear-off lid wherein a tear-off
foil (25) is connected to a lid ring (20') with a take out opening
(25) by heat sealing of a heat sealable material, characterized in
that the heat sealable material (62) is applied on the lid ring
only to the border (68) of the take out opening (25) or in the
connection area with the tear-off foil and/or that the heat
sealable material (65) is applied only to the border of the
tear-off foil.
10. Method according to claim 9 characterized in that the heat
sealable material (62, 65) is applied on the starting material (60)
before a forming or punching thereof.
11. Method according to claim 9 characterized in that the heat
sealable material (62, 65) is applied after a forming of the lid
blank (20) or lid ring (20') or after a punching of the tear-off
foil.
12. Method according to claim 9, characterized in that the heat
sealable material is applied in liquid form or is laid on as a
solid band.
13. Method according to claim 9, characterized in that the lid ring
(20') is provided with a flange directed upwardly and inwardly (67;
retort curl) and that the heat sealable coating is applied so that
the flange is at least partly covered.
14. Method according to claim 9, characterized in that the lid ring
or its starting material, respectively, is provided at least on one
side and preferably on both sides with a plastic coating that is
not suitable for heat sealing.
15. Method according to claim 14, characterized in that the coating
not suitable for heat sealing extends beneath the heat sealable
coating (62) by applying the latter as a layer on the coating not
suitable for heat sealing.
16. Method according to claim 9, characterized in that the lids are
conveyed on a linear conveying apparatus by toothed belts or by
chains to the working stations and in particular to the heat
sealing station, as the case may be with a preceding working
station along the conveying path wherein the heat sealable coating
is applied to the lid rings following each other.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Swiss patent
application No. 453/05, filed on Mar. 17, 2005, the disclosure of
which is incorporated herein by reference in its entirety.
BACKGROUND
[0002] The invention relates to a tear-off lid comprising a lid
ring with a take out opening covered by a tear-off foil and wherein
lid ring and tear-off foil are releasable connected to each other
by a hot sealable plastic coating in a connection area around the
edge of the take out opening. Further the invention relates to a
container with a tear-off lid. Still further the invention relates
to a method for the manufacture of a tear-off lid wherein a
tear-off foil is fixed by a hot sealable material to a ring shaped
lid with a take out opening.
PRIOR ART
[0003] It is known to provide lids on containers in the form of
cans or boxes, respectively, as ring shaped lids, in particular
metal lids, being permanently fixed to the container and being
provided with a take out opening in said lid which is closed by a
tear-off foil, and in particular a tear-off metal foil, fixed to
the ring shaped lid by hot sealing up to the first use of the
contents of the package. Such lids are known as tear-off lids. An
additional plastic cover that is arranged over the metal lid
provides a closure for the package during the consumption time of
the contents of the package. It is known to make the ring shaped
lid from a starting material coated on its whole surface wherein a
heat sealable coating of polypropylene or a coating containing
polypropylene has been provided on the whole surface of the upper
face of the starting material where the tear off foil will be hot
sealed. This coating is subject to the manufacturing steps during
forming of the ring shaped lid. From WO 01/07330 it is known to
apply the hot sealable full surface coating of the ring shaped lid
only after the forming thereof.
SUMMARY OF THE INVENTION
[0004] It is the object of the invention to improve a tear-off lid
of the mentioned kind.
[0005] This object is met by a tear-off lid with the characterizing
features of claim 1.
[0006] By limiting the hot sealable coating to the border of the
take out opening or only to the connection area and thus
essentially to the actual sealing area, it is possible to save a
considerable amount of hot-sealing material. It has been found that
the hot sealable coating material has disadvantages for the forming
of the lid outside of the sealing area and for example is
frequently damaged during flanging. Outside of the sealing area a
different coating of the lid can be provided, for example a coating
made of PET (polyethylene terephthalate) which is already known in
the prior art as the coating on the lower face (thus as the coating
facing the contents of the container). In this case the PET-coating
may lie beneath the hot sealable coating within the connection area
or the border of the take out opening, respectively, or may be
omitted there. The hot sealable coating is preferably a
polypropylene coating or a coating containing polypropylene, but
other hot sealable substances can be used as well.
[0007] Another object of the invention is to provide a method for
the manufacturing of tear-off lids.
[0008] This object is met for the method mentioned at the beginning
with characterizing features of claim 9.
[0009] In special embodiments of the method the hot sealable
coating is applied before applying and sealing of the foil only on
the border or the connection area, respectively, on the one hand to
the preformed or formed ring shaped lid or on the other hand to the
not yet formed starting material on the areas that later form the
border or the connection area, respectively.
[0010] In another embodiment the hot sealable coating is
specifically applied as well to the preformed ring shaped lid on
the special flange (so called "retort-curl") of the edge of the
take out opening.
[0011] In both embodiments the hot sealable coating can be applied
to the bare metallic lid ring or on the bare metallic starting
material (wherein the metal may be a metal with a metallic coating)
or on the other hand the hot sealable coating can be applied to a
lid ring that is already provided with a non metallic coating or on
a starting material that is already provided with a non metallic
coating and wherein said non metallic coating is not suitable for
hot sealing and is for example a PET coating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Further embodiments, advantages and uses of the invention
follow from the dependent claims and from the following description
and the drawings, wherein:
[0013] FIG. 1 is a schematic side view of an apparatus for
conveying and manufacturing lids;
[0014] FIGS. 2 to 8 show sectors of metal lids for the explanation
of lid manufacture;
[0015] FIG. 9 shows another preferred embodiment of a conveying
apparatus;
[0016] FIG. 10 shows the coating of starting material for the lid
ring or for the tear-off foil with hot sealable material;
[0017] FIG. 11 shows the coating of a lid ring with hot sealable
material;
[0018] FIG. 12 shows the coating of another embodiment of the lid
ring with hot sealable material;
[0019] FIG. 13 shows a coated lid ring before applying the tear-off
foil;
[0020] FIG. 14 shows a tear-off foil coated in its border area with
hot sealable material; and
[0021] FIG. 15 shows a section of an embodiment of a tear-off
lid.
WAYS OF IMPLEMENTING THE INVENTION
[0022] Known methods and apparatus for making metal lids with
tear-off foils are shown in prior art FIGS. 1 and 9, respectively.
FIGS. 2 to 8 show the result of manufacturing steps during
manufacture of such covers or lids, respectively. FIG. 1 shows a
schematic side view of an apparatus 1 which is provided with
several working stations 3 to 8 and a further station 9 arranged on
a machine frame 2. A conveyor 10, 13, 14 conveys lid parts and
finished lids with tear-off foil in conveying direction shown by
arrow C from the starting point at the staple 11 to the end of the
apparatus where the objects move by chutes into trays 16 or 17. The
objects are taken from the staple 11 in a known manner and enter
into the conveyor. The conveyor is provided with two long rails 10
each arranged on one side of the lid parts or lids, respectively.
By lifting the rails 10 in direction A by a crank drive 14, the lid
parts or lids, respectively, lying within the work stations 3 to 9
and in rests 10' between the work stations are lifted and are then
displaced by an amount in forward direction shown by arrow B
(directed in same direction as arrow C) by a crank drive 13 moving
the rails in forward direction B. The rails are then moved
downwards in direction of arrow A and the lid parts or lids,
respectively, are again placed on the rests. The rails 10 are then
moved below the rests and in backward direction of arrow B and thus
in opposite direction to arrow C and then make the same conveying
movement again. Between the conveying movements the lid parts or
lids, respectively, lie on the rests in the working stations and in
rests in between and the lid parts or lids, respectively, are
stationary within the working stations and are worked upon therein.
After all work stations have finished their working operation
another transport cycle takes place. FIG. 2 shows stapled metal
blanks 20 as an example for the lid parts of the staple 11. These
blanks are for example round metal disks. As an example their
diameter is 11 centimetres. Other basic shapes are of course
possible, such as square or rectangular shapes. Of course other
diameters can be selected. The blanks have already been preformed
at their edges as shown in FIG. 2 by means of another machine.
According to one embodiment of the present invention they may be
coated by a hot sealable material in an area only or they will be
coated according to another embodiment in a further step in this
area only. Both embodiments will be explained later. Only a sector
of each disk-shaped blank is shown in FIG. 2 and as well in the
following Figures to simplify the drawings. In the first working
station 3 of FIG. 1 the blanks are worked upon with an upper and a
lower die to punch an opening (take out opening of the lid) into
the disk, as can be seen in FIG. 3 in which the edge of the opening
is referenced as 21 and the punched out round plate is shown as 27.
This plate is moved as scrap into bin 12 of FIG. 1. The punching
working station 3 is operated by a drive 15 as it is the case as
well for the following working stations. In working station 4 the
edge 21 is drawn downwardly resulting in the shape 22 of the edge
shown in FIG. 3. The now ring shaped lid parts or lid rings 20'
respectively, are then conveyed into working station 5 wherein a
foil 25 is placed over the opening of lid ring 20' and is fixed to
the surface thereof by heat sealing, as can by seen in FIGS. 5 and
6. The underside of the metal foil may be provided to this end
according to the state of the art with full surface coating of a
plastic layer suitable for heat-sealing. The foil cut 25 that is
needed is usually punched out within station 5 from a broad sheet
of foil and placed over the middle opening of the annular disk and
in the heat sealing station the foil is pressed to the edge of the
round opening of part 20 and heat is used, so that the foil 25 is
fixed and sealed to the lid ring 20' by melting and then cooling
down of the plastic layer. This is known to the person skilled in
the art and is not explained in greater detail. A cooling station 7
may be provided for cooling down. In working station 8 an embossing
step will provide the foil 25 with an embossment 24 (FIG. 7) and
the edge 22 will beaded further to form the finished edge 23. The
finished lids 20 are tested in a testing station 9 which comprises
usually a test of air tightness for the tear-off foil 25 fixed to
the lid. If the foil is fixed to the metal ring in an airtight
manner the lid is conveyed to the bin 16 for the finished lids. If
the tested lid is not airtight it will be moved by the other shown
chute into scrap bin 17.
[0023] FIG. 13 shows an embodiment of a ring shaped lid for a
tear-off lid according to the present invention. The lid ring 20'
can be shaped similarly or identical to the lid rings or tear-off
lids, respectively, shown in FIGS. 2 to 8. In FIG. 13 the lid ring
is fully shown and as well its take out opening 25' which is later
covered by the tear-off foil 25 by sealing this foil on the lid
ring. Contrary to the state of the art and according to the
invention the hot sealable coating is provided only on the border
of the take out opening and in particular only in the actual
connection area of ring lid and tear-off foil, which is shown in
FIG. 13 by a strip 62 consisting of hot sealable plastic material.
Outside of the border of the take out opening (or of the inner
border of the lid ring, respectively) and in particular outside of
the actual connection area, there is, according to the invention,
no hot sealable plastic coating provided. Thus the remaining
surface of the lid ring 20', that means the surface being outside
of the border and in particular outside of the connection area and
in particular the surface formed for fixing to the container or the
outer border of the lid ring, respectively, is not provided with a
plastic coating, or if the case may be, only with a plastic coating
different than the hot sealable plastic coating. The hot sealable
plastic coating is in particular a polypropylene layer or a layer
containing polypropylene, for example a lacquer layer containing
such particles. Such hot sealable coating materials are known in
the prior art and are commercially used for hot sealing of tear-off
foils. A plastic coating different therefrom, and which thus forms
the sole plastic coating outside of the border of the take out
opening or connection area, respectively, may be a coating
consisting of PET (polyethylene terephthalate). Such a coating not
suitable for heat sealing may be present as well on the border or
in the connecting area, respectively, but is then situated beneath
the heat sealable coating 62. The other side of the lid ring that
is not visible in FIG. 13 can be coated as well with such a coating
different than the heat sealable coating which can as well be a
PET-coating.
[0024] FIG. 10 shows an alternative manufacturing wherein the
coating material suitable for heat sealing is applied to the
starting material for the manufacture of the lid rings. The
starting material 60 is a metal blank, which may be provided with a
metallic coating. On this metal blank a plastic coating that is not
suitable for heat sealing may be provided, which is for example the
PET-coating mentioned above. This coating can be provided on both
sides of the metal blank 60, so for example on the whole upper
surface visible in the Figure and/or as well on the lower surface
that is not visible in the Figure. On this starting material 60 the
heat sealable plastic coating, in particular the polypropylene
coating, is applied such that it will be situated on the lid blank
20 and lid ring 20', respectively, made from the starting material
60 on the border of the take out opening 25' or in the connection
area, respectively. This is shown in FIG. 10 again by the strip
like plastic coating 62, which for example can be applied by
spraying with movable nozzles 61 or can be applied as a finished
band. After the application of the heat sealable plastic coating,
making of the lid blank 20 takes place and then the making of the
lid ring 20' and of the finished lid according to FIGS. 2 to 8. The
fixing of the tear-off foil by heat sealing is done in the
generally known manner.
[0025] FIGS. 11 and 12 show other embodiments for the application
of the heat sealable coating and the making of the ring lid,
respectively. In this embodiment the heat sealable coating 62 is
applied to the preformed lid ring 20' on which the take out opening
has been made and the edge of the take out opening has been beaded.
In the alternative of FIG. 11 this is a simple flange 66 but in the
alternative of FIG. 12 this is a special flange known in the art as
"retort curl". The cut edge resulting from the making of the take
out opening, where a coating, if any, of the blank is no longer
intact, is beaded upwardly and inwardly by this kind of flanging 67
as can be seen in FIG. 12. For both alternatives the heat sealable
coating 62 is applied to the border 68 of the take out opening, for
example by a nozzle 63 which is stationary over the rotating lid
ring or which moves along the border of the stationary lid ring. In
the variant of FIG. 12 with the retort curl 67 it is preferred that
the coating 62 covers the flange, so that the cut edge is as well
enclosed by the coating.
[0026] As already explained the coating may cover on the one hand
the whole border 68 of the take out opening as shown with coating
62 of FIG. 12 or on the other hand the coating may be applied with
less width so that it covers essentially only the connection area
on which the tear-off foil is fixed. As explained above an
additional plastic coating that is not suited for heat sealing can
be provided on the lid ring, for example a PET-coating, which
covers the lid ring on those areas not covered by the heat sealable
coating 62. Relevant for the invention is in any case that the heat
sealable coating 62 does not extend over the whole upper surface of
the ring shaped lid as has been the case in the prior art. The
lower surface of the ring shaped lid can be covered by a coating
not able to be heat sealed, preferably again a PET-coating. The
formed outer border 64 for connecting the finished lid to a
container in generally known manner can be made in different known
ways and is not explained here in detail.
[0027] FIG. 15 shows the embodiment of FIG. 12 with already fixed
tear-off foil 25. Same reference numerals stand for the same
elements so in particular the heat sealable coating 62 which
extends over the retort curl 67. It is shown as well in FIG. 15
that the heat sealable coating 62 at the border of the take out
opening may extend as well over the actual connection area of
tear-off foil and border 68 which is shown by part 62' of the heat
sealable coating which extends a little bit over the connection
area and is present on the border 68 outside of the connection
area. The surface 70 of the lid with the lid ring 20' may be
provided with a coating and in particular a PET coating as already
mentioned several times, which may extend as well under the heat
sealable coating 62 on the border 68. The lower side 69 can be
provided with such a coating or with another plastic coating, which
is preferably provided already on the flat starting material. The
heat sealable coating 62 may be put on as a finished band instead
of applied by nozzles 63 in the embodiments of FIGS. 11, 12 and 15
as well.
[0028] Further FIG. 14 shows an embodiment in which a heat sealable
coating has been applied on the lower side of the tear-off foil 25
in form of a coating 65 only on the border thereof, in particular
as a strip shaped coating 65. This coating can be applied instead
of or additionally to the heat sealable coating 62 of the lid ring
and leads in the established connection of FIG. 15 essentially to
the same result in which the heat sealable coating 62 is present
only on the border 68 or within the connection area of lid ring and
tear-off foil. Here as well the width of coating 65 can be selected
such that a retort curl 67 is covered. Both coatings 62 on the ring
lid and 65 on the tear-off foil can be present. The application of
the coating 65 to the lower surface of the tear-off foil can be
done according to FIG. 10, wherein in this case the starting
material 60 is the tear-off foil material which tear-off foil is
later punched out with the tear-off flap 71 from the starting
material 60.
[0029] FIG. 9 shows a conveying apparatus 30 according to a
preferred embodiment in perspective view. This conveying apparatus
is adapted for conveying lid shaped objects of the described kind.
The conveying apparatus serves as well for the step by step
conveying of the lid parts and lids, respectively, towards each of
the working stations, which are preferably the working stations for
the manufacture of lids and the testing station 9. These stations
are not shown in FIG. 9 but it is known to the man skilled in the
art how to arrange these stations along the conveying apparatus for
performing the actual working. In FIG. 9 it is further shown that
an additional conveying apparatus 30' can be arranged adjacent the
conveying apparatus 30, which may be driven by the same drive 33,
37 or may comprise its own drive. Additional conveying means may be
provided to increase the total number of conveyed lid parts or
lids, respectively. With the shown conveying apparatus 30 lid parts
and lids, respectively, can be conveyed with a high rate of for
example 200 parts per minute and with reproducible steps between
the stations. If further results a flexible concept for a large
range of the format of the objects or lids, respectively, which may
range for example for round lids from a diameter of 50 to 200 mm
and may take up as well different rectangular formats for example
for the current fish cans. The conveying apparatus is further
designed as a compact module for one track or multi track
arrangement as shown.
[0030] In the shown preferred embodiment the conveying apparatus
comprises two toothed belts 31 and 32, in particular lying with
their surfaces in the same planes and thus running coplanar and
being led over pulleys 34, 36 at the beginning and end of the
conveying apparatus so that an endless toothed belt drive in the
necessary length for the number of working stations is provided. A
step motor or a servo motor driving the belts by toothed rollers,
as can be seen in the Figure with motor 33 and driving axle 38,
provides the stepwise toothed belt movement synchronized with the
working stations. If further conveying apparatus, as apparatus 30'
are provided, their toothed belts can be driven by the same motor
over additional driving axles or they may be provided with their
own motor drive. Motor 33 is controlled by a control 37 for making
the step by step forward movement which control 37 may be a common
control for the lid making apparatus, which controls as well the
working stations and the station 9, or which control 37 is a
control for the conveying apparatus only which is in communication
with a master control for the lid making. Motor 33 and the other
drive components for the toothed belts are arranged on a machine
bed 35 of which only feet 35 are shown. Dogs are connected to the
toothed belts which are depicted in FIG. 9 generally with 40 and
wherein dogs lying opposite each other on toothed belts 31, 32 form
an uptake for each object. The uptake formed by the dogs 40 is
moved along the conveying path and in direction of shown arrow C
from the input side of the conveying apparatus which is at the
motor position to the output side at the pulley 36 by the movement
of the belts. A cover 50 over the toothed belt and the dogs is
provided in the shown embodiment, which covers the belt and a part
of the dogs. At the position of the working stations this cover 50
is provided with a recess 52 which allows taking off the objects
from the dogs 40 so that the object can be taken away from the
dogs, worked upon in the working station and then be put back
again. Between stations there are generally provided no recesses 52
so that there the take off of objects from the dogs is blocked by
cover 50. Additionally or alternatively to the blocking by cover 50
the dogs can be magnetic which may prevent a take off of the object
during the conveying step as well if the object is made of a
material that can be held by a magnet.
[0031] It is preferred that the distance between the toothed belts
31 and 32 can be set whereby the distance of opposing dogs 40 of
the toothed belts can be adjusted to adapt the conveying apparatus
to different object sizes. To this end transverse links 58 are
provided which allow a simple setting of the distance between the
toothed belts. The drive axle 38 is adapted to allow such a
distance setting. The distances between dogs 40 on each toothed
belt are given by the spacing of the teeth of the toothed belt and
the fixation of the dogs. This distance can preferably be changed
to adapt to the object size by changing the toothed belts to
another set of toothed belts having dogs with a different distance
to each other. In this way the preferred take up size can be
provided by setting the distance between the toothed belts and
changing to toothed belts with different distances between the
dogs. Thereby a changeover to different object sizes can be done
for all dogs at the same time and quickly. The manufacturing steps
described for the tear-off lids and the corresponding working
stations and conveying apparatus are to be understood as examples
only and serve for the understanding of the invention. The
invention can be practiced as well for tear-off lids manufactured
in a different way.
[0032] For both embodiments described of the manufacturing and
conveying apparatus, respectively, wherein the heat sealable
coating is applied to the lid ring, it is necessary to provide a
corresponding working station along the conveying path and of
course ahead of the heat sealing station. For those embodiments
where the coating is applied to the starting material, the coating
is already present on the lid blanks at the beginning of the shown
manufacturing and conveying paths, respectively, and as well on the
material of the tear-off foil that only needs punching.
[0033] While there are shown and described presently preferred
embodiments of the invention, it is to be understood that the
invention is not limited thereto but may be otherwise variously
embodied and practiced within the scope of the following
claims.
* * * * *