U.S. patent application number 10/500847 was filed with the patent office on 2005-08-11 for system and method for applying opening devices onto packages.
Invention is credited to Berggren, Goran.
Application Number | 20050173438 10/500847 |
Document ID | / |
Family ID | 20286598 |
Filed Date | 2005-08-11 |
United States Patent
Application |
20050173438 |
Kind Code |
A1 |
Berggren, Goran |
August 11, 2005 |
System and method for applying opening devices onto packages
Abstract
A system (14) and a method for applying opening devices (2) onto
packages (3) of pourable food products are provided. The system
comprises a package conveyor (6) for feeding the packages along a
predetermined path (P) and an application apparatus (13) for
applying the opening device; onto the packages on the package
conveyor. The application apparatus comprises an optical detection
unit (30) for detecting an application point on one of the packages
(20) on the package conveyor. The application apparatus further
comprises a pick and place unit (36) for receiving application
information regarding the detected application point from the
optical detection unit, picking one of the opening devices and
placing it onto said one of the packages on the package conveyor by
means of the application information.
Inventors: |
Berggren, Goran;
(Staffanstorp, SE) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Family ID: |
20286598 |
Appl. No.: |
10/500847 |
Filed: |
April 14, 2005 |
PCT Filed: |
December 5, 2002 |
PCT NO: |
PCT/SE02/02232 |
Current U.S.
Class: |
220/278 |
Current CPC
Class: |
B65B 61/186 20130101;
B31B 50/84 20170801; B31B 50/006 20170801 |
Class at
Publication: |
220/278 |
International
Class: |
B65D 017/44 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 2002 |
SE |
0200029-7 |
Claims
1. A system for applying opening devices onto packages of pourable
food products, said system comprising a package conveyor for
feeding said packages along a predetermined path and an application
apparatus for applying said opening devices onto said packages on
said package conveyor, wherein said application apparatus comprises
an optical detection unit for detecting an application point on one
of said packages on said package conveyor and a pick and place unit
for receiving application information regarding said detected
application point from said optical detection unit, picking one of
said opening devices and placing it onto said one of said packages
on said package conveyor by means of said application
information.
2. A system as claimed in claim 1, wherein said application point
is defined by a prelaminated hole on said one of said packages.
3. A system as claimed in claim 1, wherein said optical detection
unit comprises a camera for recording an image of said one of said
packages, wherein said image contains said application point.
4. A system as claimed in claim 3, wherein said optical detection
unit further comprises processing means for producing said
application information means for producing said application
information by comparing said image with a reference image
containing a reference system, and obtaining a location of said
application point with respect to said reference system.
5. A system as claimed in claim 4, wherein said reference system
includes an ideal location of the application point corresponding
to the application point on a perfect package.
6. A system as claimed in claim 4, wherein said reference system
includes an ideal location of the application point in relation to
a mark being fixed with respect to said package conveyor, said
ideal location corresponding to the application point on a perfect
package.
7. A system as in claim 1, wherein said application information
contains a movement pattern for said pick and place unit for
placing said one of said opening devices onto said one of said
packages.
8. A system as claimed in claim 1, wherein said optical detection
unit is arranged integral with said pick and place unit.
9. A system as claimed in claim 1, wherein said optical detection
unit is arranged adjacent to said package conveyor at a distance
from said pick and place unit.
10. A system as claimed in claim 1, wherein said pick and place
unit comprises at least one robot with at least one robot arm.
11. A system as claimed in claim 1, wherein said pick and place
unit comprises at least one robot with three robot arms said at
least one robot being able to operate in three dimensions.
12. A system as claimed in claim 1, wherein said application
apparatus further comprises a gluing unit for applying glue onto
said opening devices before picking.
13. A system as claimed in claim 1, wherein it further comprises a
supply station for feeding said packages to said package
conveyor.
14. A system as claimed in claim 1, wherein it further comprises a
package support rail for supporting said packages during the
application of said opening devices by securing said packages
between said support rail and said package conveyor.
15. A system as claimed in claim 14, wherein said package support
rail is adjustable to permit application of opening devices onto
packages of various sizes.
16. A system as claimed in claim 1, wherein it further comprises a
number of separated guiding devices for guiding said packages, said
guiding devices being fixed to and movable with said package
conveyor so as to feed said packages along said predetermined
path.
17. A system as claimed in claim 16, wherein said guiding devices
each comprises at least one carrier finger for supporting and
conveying said packages.
18. A system as claimed in claim 1, wherein it further comprises a
feeding apparatus for feeding said opening devices to said
application apparatus.
19. A system as claimed in claim 12, wherein it further comprises a
feeding apparatus for feeding said opening devices to said gluing
unit, whereupon said opening devices are being picked by said pick
and place unit.
20. A method for applying opening devices onto packages of pourable
food products, comprising the steps of feeding said packages along
a predetermined path by a package conveyor and applying said
opening devices onto said packages on said package conveyor,
wherein it further comprises the steps of optically detecting an
application point on one of said packages on said package conveyor;
producing, from said optically detected application point,
application information for controlling a pick and place unit; and
picking one of said opening devices and placing it onto said one of
said packages on said package conveyor by means of said pick and
place unit and in accordance with said application information.
21. A method as claimed in claim 20, wherein said application point
is defined by a prelaminated hole on said one of said packages.
22. A method as claimed in claim 20, wherein it further comprises
the step of recording an image of said one of said packages,
wherein said image contains said application point.
23. A method as claimed in claim 22, wherein said application
information is produced comparing said image with a reference image
containing a reference system, and obtaining a location of said
application point with respect to said reference system.
24. A method as claimed in claim 23, wherein said reference system
includes an ideal location of the application point corresponding
to the application point on a perfect package.
25. A method as claimed in claim 23, wherein said reference system
includes an ideal location of the application point in relation to
a mark being fixed with respect to said package conveyor, said
ideal location corresponding to the application point on a perfect
package.
26. A method as claimed in claim 20, wherein said application
information contains a movement pattern for said pick and place
unit for placing said one of said opening devices onto said one of
said packages.
27. A method as claimed in claim 20, wherein it further comprises
the step of applying glue to said opening devices before
picking.
28. A method as claimed in claim 20, wherein it further comprises
the step of feeding said packages to said package conveyor.
Description
TECHNICAL FIELD
[0001] The present invention relates to a system and a method for
applying opening devices onto packages of pourable food products,
said system comprising a package conveyor for feeding said packages
along a predetermined path and an application apparatus for
applying said opening devices onto said packages on said package
conveyor.
BACKGROUND ART
[0002] As is known, many pourable food products, such as fruit
juice, UHT (ultra-high-temperature processed) milk, wine, tomato
sauce, etc., are sold in packages made of sterilized packaging
material.
[0003] A typical example of such a package is the
parallelepiped-shaped package for liquid or pourable food products
known as Tetra Brik Aseptic (registered trademark), which is formed
by folding and sealing a web of laminated packaging material. The
packaging material has a multi-layer structure comprising a layer
of fibrous material, e.g. paper, covered on both sides with layers
of heat-seal plastic material, e.g. polyethylene, and, in the case
of antiseptic packages for long-storage products, such as UHT milk,
also comprising a layer of oxygen-barrier material defined, for
example, by an aluminium film, which is superimposed on a layer of
heat-seal plastic material and is in turn covered with another
layer of heat-seal plastic material eventually defining the inner
face of the package contacting the food product. As is known, such
packages are made on fully automatic packaging machines, in which a
continuous tube is formed from the web-fed packaging material; the
web of packaging material is sterilized in the packaging machine
itself, e.g. by applying a chemical sterilizing agent, such as a
hydrogen peroxide solution, which, after sterilization, is removed,
e.g. vaporized by heating, from the surface of the packaging
material; and the web of packaging material so sterilized is
maintained in a closed sterile environment, and is folded and
sealed longitudinally to form a vertical tube. Of course it is
possible to use other methods for sterilizing the packaging
material.
[0004] The tube is filled with the sterilized or sterile-processed
food product, and is sealed and cut at equally spaced cross
sections to form pillow packs, which are then folded mechanically
to form the finished, e.g. substantially parallelepiped-shaped,
packages.
[0005] Alternatively, the packaging material may be cut into
blanks, which are formed into packages on forming mandrels, and the
resulting packages are filled with the food product and sealed. One
example of such a package is the so-called "gable-top" package
commonly known by the trade name Tetra Rex (registered
trademark).
[0006] Another example of a package for pourable food products is
the parallelepiped-shaped package known as Tetra Brik (registered
trademark). The main difference between Tetra Brik and Tetra Brik
Aseptic is that Tetra Brik does not comprise an oxygen-barrier
layer since it is mainly used for "ordinary" pasteurised milk
products.
[0007] Once formed, packages of the above type may undergo further
processing, such as the application of a closable opening device
constituting the pouring part of a package.
[0008] The most commonly used opening device comprises a frame
defining an opening and fitted about a pierceable or removable
portion of the top wall of the package; and a cap hinged or screwed
to the frame and which can be removed to open the package. Other,
e.g. slidable, opening devices are also known to be used.
[0009] The pierceable portion of the package may be defined, for
example, by a so-called "prelaminated" hole, i.e. a hole formed in
the fibrous layer of the packaging material before the fibrous
layer is joined to the barrier layer, which is thus whole and
closes the hole to ensure hermetic, aseptic sealing, while at the
same time being easily pierced.
[0010] The application of an opening device onto a package calls
for extremely accurate positioning of the opening device with
respect to the prelaminated hole. Applying the opening device in a
wrong position may result in various problems, such as poor
adhesion of the opening device onto the package, difficulties in
opening the package, product leakage, or splashing when the product
is poured out of the package.
[0011] In the case of antiseptic packaging machines, the opening
devices are normally fitted continuously straight onto the formed
packages on on-line application units downstream from the packaging
machine. The application is mechanical, i.e. the packages abut
against some kind of holding means and the edges of the packages
are used to position opening devices on them, the application
position on each package being at a predetermined distance from its
edges. This means that the opening devices will be applied at the
same spot on every package. For several reasons, the packages to be
provided with opening devices are not identical. This means that
the distance from the prelaminated hole on a package to its edges
differs from package to package. Thus, on many packages the opening
devices will not be applied precisely about the prelaminated hole,
causing malfunctioning of the package.
[0012] EP 0 842 041 discloses a method and device for bonding
pouring spouts to flat-topped parallelepipedical cartons filled
with free-flowing products. In EP 0 842 041, separated cartons on a
conveyor belt are fed horizontally. Above the conveyor belt, a
suspension chain is arranged, said chain being provided with a
number of pouring spouts carriers for the bounding of the pouring
spouts to the cartons, the distance between said carriers being
equal to the distance between said separated cartons on said
conveyor belt. A detector is provided to sense the presence of a
pouring spout in a pouring spout carrier. If the detector senses
such a presence, a package is loaded onto the conveyor belt and the
pouring spout is applied with adhesive and bound to the package.
Even in this case the application is mechanical which can cause the
pouring spouts to be inaccurately bounded to the cartons since the
bounding occurs in the same position relative the carriers on every
carton, independently of the correct application positions.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide a system
and a method for applying opening devices onto packages of pourable
food products, which system and method eliminate the aforementioned
problems concerned with prior art. The basic concept of the
invention is to use optical detection to locate where on a package
an opening device is to be applied, that is to locate an
application point on the package. The invention thus enables
extremely accurate positioning of the opening device onto the
package independently of its shape, as long as the application
point is visible. Even if the package for some reason has a shape
deviating from the ideal shape, it will be provided with the
opening device in the correct position since no part of the package
is used as a reference for the provision.
[0014] The system and the method for achieving the object above are
defined in the appended claims and discussed below.
[0015] The system according to the present invention has a package
conveyor for feeding the packages successively along a
predetermined path. Along this path, the packages are being
subjected to different operations. The system further has an
application apparatus for continuously applying the opening devices
onto the packages. The application apparatus is preferably located
adjacent to the package conveyor to enable the application of the
opening devices on the packages when they pass by on the package
conveyor.
[0016] To detect an application point on one of the packages, the
application apparatus has an optical detection unit. By means of
this detection unit the application point can be read reliably.
Since the appearance of the package does not affect the detection
of the application point, there will be no interference from
disturbing factors, such as e.g. a potential deformation of the
package. This means that even a deformed package, having other
dimensions than the ideal package, will be provided with an opening
device exactly on top of the application point. If optical
detection had not been used, that is if instead mechanical clamping
had been used, the opening device would have been misplaced with
respect to the application point. Thus, the optical detection also
allows for application of opening devices on packages of different
sizes, since the application point is not estimated from the
dimensions of the package.
[0017] The application apparatus further has a pick and place unit
for the actual picking and placing of the opening devices. The pick
and place unit is arranged to receive application information
regarding the detected application point on a package from the
optical detection unit. It is further arranged to pick one of the
opening devices and placing it onto the package by means of the
application information. The application information for one
particular package is unique and depends on the appearance of the
it.
[0018] The application point on a package is preferably defined by
a prelaminated hole on the package. This means that the opening
device, for a correct application, is to be placed over the
prelaminated hole to enclose and cover it.
[0019] The optical detection unit advantageously has a camera for
recording an image of a package, which image contains the
application point of the package. This image can then be used to
obtain the unique application information for the package. The
optical detection unit also has processing means for producing the
application information. This is done by comparing the recorded
image with a reference image containing a reference system, and
then obtaining a location of the application point with respect to
the reference system.
[0020] The reference system preferably includes a predetermined,
memorized, ideal application point for one type of package. The
ideal application point is defined by the location of the
application point on a perfect package. By a perfect package means,
a package having the desired dimensions, being undeformed and
having the application point located optimally with respect to the
function of the package.
[0021] Alternatively, the reference system includes a
predetermined, memorized, ideal location of the application point
in relation to a mark, which mark is fixed with respect to the
package conveyor. Also in this case the ideal location corresponds
to the application point on a perfect package.
[0022] The application information preferably contains a unique
movement pattern for the pick and place unit for placing the
opening device onto the package. Thus, the pick and place unit
picks the opening device, receives the movement pattern and moves
according to this pattern to place the opening device onto the
package.
[0023] The optical detection unit is with advantage arranged
integral with the pick and place unit. The detection of the
application point on the package and the application of the opening
device on it, can then be done continuously.
[0024] As an alternative, the optical detection unit can be
arranged adjacent to the package conveyor at a distance from the
pick and place unit. In this case, the speed of the package
conveyor must be known so that the location of the application
point on the package, at a certain time, can be calculated to
obtain the unique application information for that package.
[0025] The pick and place unit has at least one robot with at least
one robot arm. However, the pick and place unit advantageously has
at least one robot with three robot arms. This robot is able to
operate in three dimensions so as to allow full movement ability of
the pick and place unit.
[0026] Preferably, the application apparatus further includes a
gluing unit for applying glue onto the opening devices before they
are picked by the pick and place unit, to make them adhere onto the
packages.
[0027] The system further has a supply station for feeding the
packages to the package conveyor. In the supply station, packages
from the filling machine are prearranged to have a certain mutual
distance when they are automatically fed, one by one, from the
supply station to the package conveyor.
[0028] Preferably, the system further has a package support rail
for supporting the packages during the application of the opening
devices. This is done by securing the packages between the support
rail and the package conveyor. The package support rail is
preferably adjustable to allow the distance between itself and the
package conveyor to be varied, so that opening devices can be
applied to packages of different sizes.
[0029] A number of separated guiding devices for guiding the
packages are preferably comprised in the system. The guiding
devices are then fixed to, and move with, the package conveyor so
as to feed the packages along the above mentioned predetermined
path. Besides supporting and carrying the packages, the guiding
devices also provide for the packages being separated by an
appropriate distance for the operations to be performed on the
packages on the package conveyor. The distance between the guiding
devices is preferably adjustable to fit different package
sizes.
[0030] Each of the guiding devices advantageously includes at least
one carrier finger for the supporting and conveying of the
packages. The carrier fingers preferably have a shape, and are
fixed to the package conveyor in a way, that is suitable for the
appearance of the packages. For example, if the packages are
parallelepiped-shaped, the carrier fingers can simply be
rectangular plates projecting radially from the package conveyor,
with the packages abutting against the plates by one of the
walls.
[0031] Finally, the system further includes a feeding apparatus for
feeding the opening devices to the application apparatus, or more
particularly, to the gluing unit, whereupon they are picked by the
pick and place unit.
[0032] The method according to the present invention comprises the
steps of feeding the packages along a predetermined path by a
package conveyor and applying the opening devices onto the packages
on the package conveyor. The method further includes the steps of
optically detecting an application point on a package on the
package conveyor; producing, from the optically detected
application point on the package, application information for
controlling a pick and place unit; and picking an opening device
and placing it onto the package on the package conveyor by means of
the pick and place unit and in accordance with the application
information.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 shows a system according to the present
invention.
[0034] FIG. 2 is a top plan view of a package.
[0035] FIG. 3 is a top plan view of a package according to an
alternative embodiment of the invention.
[0036] FIG. 4 is block diagram describing the application apparatus
in a system according to the present invention.
[0037] FIG. 5 shows the pick and place unit in the application
apparatus in FIG. 4.
[0038] FIG. 6 is flowchart illustrating the method according to the
present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0039] FIG. 1 is a schematic plan view of a system 1 for applying
opening devices 2 onto packages 3 of pourable food products.
[0040] The packages 3 are made in a packaging machine (not shown)
from a web of sheet packaging material comprising a layer of paper
material covered on both sides with layers of heat-seal plastic
material, e.g. polyethylene, and optionally a layer of barrier
material, e.g. aluminium, located on the inside of the paper
material layer and in turn covered on the inside with another layer
of plastic material.
[0041] A top face 4 of each package 3, which, in the illustrated
example, are substantially parallelepiped-shaped, has a pierceable
portion 5 conveniently defined by a so-called "prelaminated" hole,
i.e. a hole formed in the paper layer of the packaging material
before the paper layer is joined to the barrier layer, which thus
closes the hole to ensure hermetic, aseptic sealing, while at the
same time being easily pierced.
[0042] The system 1 comprises a package conveyor 6 moving at a
constant speed along a path defined by two drive means 7 and 8,
respectively. The package conveyor 6 supports a number of guiding
devices 9 for guiding packages 3, wherein the guiding devices are
fixed in equally spaced manner to, and project radially from, the
package conveyor 6. Each of the guiding devices 9 includes two
carrier fingers 10a and 10b, respectively, for supporting and
conveying one package, the package abutting against the carrier
fingers 10a-b by two opposite walls and against the package
conveyor 6 by an intermediate wall, the distance between said
carrier fingers thus being essentially equal to the distance
between said opposite walls.
[0043] The guiding devices 9 receive the packages 3 from an input
conveyor 11, one package being fed into each of the guiding
devices. The input conveyor 11 is located adjacent to the package
conveyor 6 and tangent to the same at a supply station 12. It
conveys the packages 3 from the filling machine (not shown) in
equally spaced manner and at a constant speed equal to the linear
speed of the guiding devices 9. Rotating together with the package
conveyor 6, the guiding devices 9 feed the packages 3 along a path
P through an application apparatus 13 for applying the opening
devices 2 onto the packages 3, the application apparatus 13 being
located adjacent to the package conveyor 6. The path P begins with
the supply station 12 and ends with an unloading station 14 where
the packages 3 are removed from the package conveyor 6.
[0044] The application apparatus 13 comprises a gluing unit 15 for
applying glue onto the opening devices 2 and a picking unit 16 to
which the opening devices are fed after the glue application.
[0045] The system 1 includes a feeding apparatus 17 for feeding the
opening devices 2 from a sorter 18 to the gluing unit 15 and
further onto the picking unit 16 in the application apparatus 13.
The system 1 further includes a package rail support 19 for
supporting the packages 3 during the application of the opening
devices 2. The package support rail 19 is arranged essentially
parallel to the package conveyor 6 along the horizontal part of the
path P and secures the packages 3 between itself and the package
conveyor 6. To permit application of opening devices onto packages
of various sizes, the package support rail 19 is adjustable in
height, i.e. the uniform distance from the package support rail 19
to the package conveyor 6 is variable.
[0046] FIG. 2 and 3 are two top plan views of a package 20 showing
a pierceable portion in shape of a prelaminated hole 21. The centre
22 of the hole is used to define the location of the same. The
location of the prelaminated hole is not the same on every package.
The dashed circle 23 in the figures represents the ideal location
of a prelaminated hole, i.e. the location of the prelaminated hole
on a perfect package.
[0047] In FIG. 2 the ideal location of the prelaminated hole, or
more particularly the centre 24 of it, is used as a reference
system to express the location of the centre 22 of the actual
prelaminated hole 21 on the package 20. The deviation of the
prelaminated hole 21 from the ideal location 23 (strongly
exaggerated to make it more clear) is represented by the arrow 25
between the centre 24 and the centre 22. The arrow 25 can be
divided into a horizontal component 26 and a vertical component 27
describing the deviation of the prelaminated hole 21 in horizontal
and vertical directions, respectively.
[0048] FIG. 4 is a block diagram illustrating the construction of
the application apparatus 13. In addition to the above discussed
gluing unit 15 and the picking unit 16, the application apparatus
13 comprises an optical detection unit 30 for detecting the centre
22 of the prelaminated hole 21 on each of the packages 3.
[0049] The optical detection unit 30 in turn comprises a sensor 31
for generating a signal enabling a camera 32, e.g. one of CCD-type,
for recording an image of the top of each of the packages 3, the
image showing the prelaminated hole and its centre. The optical
detection unit 30 further comprises a memory 33 for storing a
reference image with a reference system represented by the ideal
location discussed above, and processing means 34 arranged to
compare the recorded image with the reference image, more
particularly, the prelaminated hole in the recorded image with the
reference system. The result of this comparison, i.e. the deviation
of the prelaminated hole from the ideal location in horizontal and
vertical directions, respectively, is thereafter used to produce
application information needed for the application of the opening
devices 2 onto the packages 3. The optical detection unit 30 also
comprises transmitting means 35 for transmitting this application
information regarding the detected prelaminated hole.
[0050] The application apparatus 13 further comprises a pick and
place unit 36 for picking the opening devices 2 from the picking
unit 16 and placing them onto the packages 3.
[0051] The pick and place unit 36 in turn comprises receiving means
37 for receiving said transmitted application information and a
robot 38. The application information contains a movement pattern
for the pick and place unit 36 describing the movement for the same
from a reference position to place one opening device onto one
package very accurately on top of its prelaminated hole.
[0052] In the preferred embodiment the robot 38, described further
in FIG. 5, is a picking robot, type IRB 340, commercially available
from ABB Flexible Automation AB, Vster.ang.s Sweden. It has three
robot arms 39a-c being joined together at one end at 40, the robot
38 being able to operate in three dimensions. The robot 38 is at 40
provided with jaws 41 for picking and placing the opening devices 2
onto the packages 3, the jaws 41 closing when picking, and opening
when placing, an opening device.
[0053] The optical detection unit 30 is preferably arranged
integral with the pick and place unit 36, the camera 32 25 being
arranged adjacent to the jaws 41.
[0054] FIG. 6 is a flowchart illustrating the method according to
the present invention. Every box in the flowchart corresponds to
one step in the method. The operations are obviously performed
cyclically with a period equal to the time required by the package
conveyor 6 to move the distance between two subsequent packages
3.
[0055] First there are two branches in the flowchart which later
merge into one. The opening devices 2 are sorted in the sorter 18
(step 42), fed from the sorter 18 to the gluing unit 15 by the
feeding apparatus 17 where they are provided with glue (step 43)
and further fed to the picking unit 16 (step 44). Simultaneously,
the packages 3 from the packaging machine are being loaded onto the
input conveyor 11 (step 45) and then supplied onto the package
conveyor 6 feeding them to the application apparatus 13 (step 46).
One of the glued opening devices is picked by the pick and place
unit 36 (step 47) from the picking unit 16. To avoid acquiring and
processing an excessive amount of data, the sensor 31 generates a
trigger pulse to enable the camera 32 (step 48). The camera then
records an image of the top of one of packages 3, said image
showing the prelaminated hole and its centre (step 49). In the
memory 33, a reference image, containing the reference system
discussed above, is stored. On the basis of conventional image
processing, the deviation of the prelaminated hole with respect to
its ideal location is determined and a movement pattern for the
robot 38 is produced (step 50) based on said deviation. The
movement pattern is transmitted from the optical detection unit 30
and received by the pick and place unit 36 (step 51). The pick and
place unit 36 follows the movement pattern from a reference
position and places the opening device accurately on top of the
prelaminated hole of the package (step 52). Finally the packages
provided with opening devices are unloaded at the unloading station
14 (step 53).
[0056] As an alternative to the above, the reference system
required for the application may be implemented by a mark 29 on a
guiding device 28. In FIG. 3 the package 20 is shown together with
a part of the guiding device 28, said guiding device being provided
with the mark 29. The mark 29 and the ideal location of the
prelaminated hole 23 constitute the reference system in this
alternative embodiment. On a perfect package, the distance between
the mark 29 and the ideal location of the prelaminated hole 23, or
more particularly the centre 24 of it, is x.sub.0 and y.sub.0 in
horizontal and vertical directions, respectively. In the figure the
distance between the mark 29 and the location of the centre 22 of
the actual prelaminated hole 21 is x.sub.1 and y.sub.1 in
horizontal and vertical directions, respectively, the expressions
.vertline.x.sub.0-x.sub.1.vertline. and
.vertline.y.sub.0-y.sup.1.vertlin- e. describing the deviation of
the prelaminated hole 21 from the ideal location 23 in respective
directions.
[0057] The above described examples shall only be seen as examples.
A person skilled in the art realizes that the embodiments discussed
can be varied in a number of ways without deviating from the
inventive conception.
[0058] As an example, the opening devices do not have to be glued
onto the packages. Alternatively, the opening devices can be heated
and then sealed onto the packages.
[0059] The pick and place unit can comprise more than one robot,
allowing more than one application at a time, speeding up the
production.
[0060] The optical detection unit and the pick and place unit do
not have to be arranged integral with each other. According to an
alternative embodiment the optical detection unit is arranged
adjacent to the package conveyor at a distance from the pick and
place unit. If the speed of the package conveyor is known, the
location of the centre of the prelaminated hole on a package at a
certain time can be determined and the application information can
be produced and transmitted to the pick and place unit.
* * * * *