METHOD FOR CONTROLLING A PACKAGING MACHINE

PROCEDE DE COMMANDE D'UNE MACHINE D'EMBALLAGE

English Abstract

The invention relates to a method for controlling a packaging machine, which
comprises a product conveyor for conveying a product and a packaging conveyor
for conveying a packaging. Said conveyors run, in sections, parallel and
synchronous to one another whereby enabling the product to be introduced into
the packaging inside a transfer station. The packaging machine additionally
comprises an including conveyor for including an inclusion part to be enclosed
with the product, for example, a pamphlet or a measuring scoop. A data memory
provided in the form of a shift register contains different state data and
control data pertaining to the packaging units consisting of the product,
packaging and the inclusion part. The data, at time t~0, are displaced in the
shift register in a clocked manner. At at least time t~p, which is given by an
initiator, a monitoring or processing action is initiated on the inclusion
part, whereby time t~p can be shifted with regard to time t~0. The relative
position of time t~p with regard to time t~0 is checked, and time t~p is
shifted when it is located within a tolerance period of time T formed around
time t~0.

French Abstract

L'invention concerne un procédé de commande d'une machine d'emballage, présentant un transporteur de produit, destiné à transporter un produit, et un transporteur d'emballage, destiné à transporter un emballage, lesquels se déplacent par sections parallèlement et de manière synchrone l'un par rapport à l'autre, de sorte que le produit peut être introduit, dans une station de transfert, dans ledit emballage. Ladite machine possède un transporteur de produit joint, destiné à transporter un produit à ajouter au produit, par exemple une notice ou une cuiller doseuse. Une mémoire de données sous forme d'un registre à décalage contient différentes données d'état et de commande relatives à des emballages unitaires constitués du produit, de l'emballage et du produit joint. Lesdites données sont déplacées à un instant t0 dans ledit registre à décalage de manière cadencée. A au moins un instant tp prédéterminé par un initiateur, une action de contrôle ou de travail commence sur un produit joint, l'instant tp pouvant être réglé par rapport à l'instant t0. Ledit procédé est caractérisé en ce que la position relative de l'instant tp par rapport à l'instant t0 est contrôlée et que l'instant tp est décalé lorsqu'il se trouve à l'intérieur d'un intervalle de temps de tolérances T formé autour de l'instant t0.

Claims

8
Claims
1. Method for controlling a packaging machine which comprises a
product conveyor for a product and a package conveyor for a package
which extend, in sections, parallel and synchronous to each other,
such that the product can be inserted into the package in a transfer
station, and with a conveyor for an additional part to be added to the
product, e.g. a leaflet or a dosing spoon, and comprising a data
storage in the form of a shift register which contains various state and
control data of packaging units which consist of the product, the
package and an additional part, wherein the data is displaced in a
clocked manner in the shift register at a point in time t o, and with at
least one point in time t p at which a control or processing action on
the additional part is started, wherein the point in time t p can be
adjusted relative to the point in time to in dependence on the product
and/or the package and/or the additional part, characterized in that
the relative position between the time t p and the time to is examined
and the time t p is shifted if it is within a tolerance period T about the
time t o.
2. Method according to claim 1, characterized in that the time t p is
shifted until it is outside of the tolerance period T.
3. Method according to claim 1 or 2, characterized in that the tolerance
period T is ~3% to ~10% of the cycle time of the packaging machine.
4. Method according to claim 3, characterized in that the tolerance time
T is ~5% of the cycle time of the packaging machine.
5. Method according to any one of the claims 2 through 4, characterized
in that the shifts .DELTA.t1, .DELTA.t2 of the time t p which are required to
obtain a

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position outside of the tolerance period T, are determined in both
directions (earlier - later) and the time t p is shifted by the smaller of
the two shifts .DELTA.t1, .DELTA.t2.

Description

CA 02475513 2004-08-06
Method for Controlling a Packaging Machine
The invention concerns a method for controlling a packaging machine
comprising a product conveyor for a product and a package conveyor for a
package which partially extend parallel and synchronously with respect to
each other such that the product can be inserted into a package at a
transfer station, and with a conveyor for an additional part to be added to
the product, e.g. a leaflet or a dosing spoon, and having a data storage in
the form of a shift register which contains various state and control data
of packaging units which include the product, the package and an
additional part, wherein the data is displaced in a clocked manner in the
shift register at a point in time to, and with at least one point in time tP
given by an initiator at which a control or processing action on the
additional part is started, wherein the point in time tP can be adjusted
relative to the point in time to in dependence on the product and/or the
package and/or the additional part.
For packaging products in a transfer device of a packaging machine, the
motions of a first circulating package conveyor for the package, e.g. a so-
called folding box chain, and of a second circulating product conveyor for
the products, e.g. a so-called product chain, are conventionally
synchronized such that the product can be inserted laterally into the
folding box transversely to the direction of motion of the chains. To
change the format, the two chains can be adjusted relative to each other.
For certain products, e.g. medication, an additional part which may e.g.
be a leaflet, a side note or a dosing spoon may have to be inserted into
the package. A leaflet is taken below as an example of this additional part.
The packaging machine has a further circulating additional part conveyor,

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e.g. a so-called leaflet tong chain which carries several tong-tike holders
which each receive and clamp one leaflet. A leaflet to be inserted into the
package is moved between the product and the folding box by the leaflet
tong chain, and carried along by the product through the lateral inserting
motion thereof to be introduced into the folding box, wherein the tong-like
holder opens as soon as the product abuts the leaflet.
The packaging machine stores a data set for each packaging unit which
comprises the product, the folding box and the leaflet, and which contains
all essential state and control data of the packaging unit. Since a plurality
of packaging units are simultaneously processed in and run through the
packaging machine, the data sets are conventionally filed in a common
data storage. The data storage is designed as a shift register, wherein the
data sets are displaced, i.e. shifted, within the shift register in a clocked
manner in accordance with the working cycle of the machine, i.e. the
changing position of the associated packaging unit in the packaging
machine up to the ejecting station. The shift register is clocked via a shift
cycle which is usually tapped by the drive of the product chain.
To provide the folded leaflet, it must usually undergo several examination
and processing steps. The leaflet must be received by a so-called leaflet
apparatus from a leaflet pile of unfolded leaflets at a certain point in time
(request time tp) and subsequently be folded. The leaflet must then be
transferred to a tong-like holder of the leaflet tong chain at a
predetermined point in time. Additionally, the correctness of the leaflet
type must be checked through detection and evaluation of a code
provided on the leaflet at a certain point in time within the leaflet
apparatus. The point in time of introduction or initiation of the respective
action is predetermined either via rotating mechanical cams which trigger
an initiation signal at a certain rotation or via an electronic reproduction
of
a corresponding cam. The initiation signals are thereby only triggered if a

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previous examination of some data of the data set in the shift register
indicates that the packaging unit is properly combined, i.e. that a product
and a packaging are present.
A packaging machine must be able to process products and also
packagings of various formats as well as various leaflet formats.
Depending on the product sizes, the packaging sizes and the leaflet sizes,
the individual components of the transfer station of the packaging
machine must be adjusted relative to each other. For format change, the
leaflet apparatus and/or the leaflet tong chain are usually adjusted
relative to the product chain and/or the folding box chain. This causes the
points in time which are predetermined by one or more initiators or cams,
to also be adjusted relative to the shift time to of the shift register which
defines the start of a processing cycle of the packaging machine. The
request time tp for the leaflet from the leaflet pile is used as an example
below, however, similar problems also occur at other times when a control
or processing action on an additional part, e.g. a leaflet, is started.
Due to adjustment of the request time tp for the leaflet relative to the shift
time to of the shift register, a situation may occur wherein the two points
in time coincide or are at least sufficiently close to each other that the
controller does not recognize and process them as two independent
signals. This can result in incompatible control runs and inadmissible
operating states which cause the packaging machine to switch off,
signalling an error. To eliminate the error, the mechanical and electronic
settings of the packaging machine and, in particular, of the leaflet
apparatus relative to the product chain must be changed until a safe
operating state is provided. Such an adjustment is possible, since there is
a certain time tolerance during transfer of the leaflet to the tong-like
holder of the leaflet tong chain. However, elimination of the error is

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demanding and has a disadvantageous effect on the efficiency of the
packaging machine.
It is the underlying purpose of the invention to produce a method for
controlling a packaging machine of the above-mentioned kind which
reliably eliminates any error due to coinciding or unacceptably close points
in time, as mentioned above.
This object is achieved in accordance with the invention in that the
relative position of the request time tP for the leaflet relative to the shift
time to of the shift register is examined and the time tP is shifted if it is
within a tolerance period T about the point in time to.
After adjustment of the packaging machine through format change and
associated adjustment of the request time tp for the leaflet relative to the
shift time to of the shift register, a controller checks whether the point in
time tP of the leaflet request coincides with the shift time to of the shift
register or is at least sufficiently close that a conflict can be expected.
This
is the case if the request time tP of the leaflet is within a predetermined
tolerance period or interval T which is disposed about the shift time to of
the shift register. If the examination shows that the request time tp of the
leaflet is within the tolerance period T, the request time tP for the leaflet
is
automatically shifted by the controller. This shift is possible without
influencing the operation of the packaging machine, since, during transfer
of the leaflet to the tong-like holder of the leaflet tong chain, there is a
certain time tolerance which is utilized in accordance with the invention. A
switching off of the packaging machine after format change due to
incompatible operating states or control runs is thereby reliably
prevented.

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A quickly operating packaging machine performs approximately 450
working cycles per minute such that the cycle time is approximately
133.33 ms. The cycle time is the time interval which the control program
requires for working. The cycle time may e.g. be 5ms. The tolerance
period T around the shift time to of the shift register should therefore be
at least 3% of the cycle time of the packaging machine, i.e. the request
time tp of the leaflet should not coincide with the last 3% of the previous
working cycle before the shift time to or the first 3% of the next working
cycle after the shift time to. A value of ~10% of the cycle time of the
packaging machine has proven to be reasonable as an upper limit for the
tolerance period T. The tolerance period is preferably ~5% of the cycle
time of the packaging machine.
If the controller determines that the request time tp is within the tolerance
time T, the request time tp is shifted until it is outside of the tolerance
time T. This shift is possible in both directions on the time axis, i.e. in
the
direction of an earlier or later point in time. In a preferred embodiment of
the invention, the controller determines the two shifts oti and ot2 of the
request time tp which are required to obtain a position outside of the
tolerance time period T in both directions (earlier, later). The request time
tp is subsequently shifted into the direction with less shift to obtain a
position outside of the tolerance time T.
Further details and features of the invention can be extracted from the
following description of an embodiment with reference to the drawing.
Fig. 1 shows the points in time to and tP on the time axis t in an uncritical
arrangement before format adjustment;
Fig. 2 shows the points in time to and tP on the time axis t in a critical
arrangement after format adjustment; and

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Fig. 3 shows the points in time to and tP on the time axis t in an uncritical
arrangement after correction.
Fig. 1 shows a time axis t which shows a shift time to of the shift register
which simultaneously also defines the start of a working cycle of the
packaging machine. The time interval between a request time tP for a
leaflet in a leaflet apparatus and the shift time to is sufficient, such that
no
critical operating states are generated in the packaging machine.
After format adjustment, wherein the temporal processes of the leaflet
apparatus relative to the product chain are adjusted, the position of the
request time tP of the leaflet relative to the shift time to of the shift
register has also changed. The request time tP for the leaflet is now much
closer to the shift time to of the shift register than before format
adjustment (Fig. 2). When the format has been changed, a controller of
the packaging machine checks whether the request time tP for the leaflet
is within a tolerance period or interval T about the shift time to of the
shift
register which is ~5% of the cycle time of the packaging machine. The
embodiment of Fig. 2 shows that the request time for the leaflet is within
the tolerance period T. The controller subsequently determines a first time
shift Otl which is required to shift the request time tp to an earlier
position
such that it is directly before the tolerance period T. A second time shift
ot2 is correspondingly determined which is required to shift the request
time tp to a later time, such that it is just outside of the tolerance period
T. The two time shifts otl and ~t2 are compared and the leaflet apparatus
is subsequently adjusted such that the request time tp is adjusted by the
smaller value (absolute value) of the two determined time shifts Otl and
Ot2 in the associated direction. In the embodiment shown ~t2«tl, which is
why the request time tP is delayed by the time period Ot2 to a later time as
shown in Fig. 3. In this state, in which the request time tP is now outside

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of the tolerance period T about the shift time to of the shift register after
displacement, incompatible runs and operating states in the packaging
machine due to excessively close initiation points or signals are reliably
eliminated.