Technical Field
[0001] The invention relates to a machine for printing hollow articles such as cans, tubes,
cartridges, other types of containers or closures.
Background Art
[0002] Corresponding machines are known. Often, they include offset printing stations that
are integrated within machine lines that include associated stations arranged upstream
or downstream, respectively. An example for an upstream station is a base coating
station (with a corresponding drying station). Examples of downstream stations are
drying or over varnish stations (with corresponding further drying stations).
[0003] The stations are arranged along a main transport direction. Together with further
stations such as the initial forming stations as well as intermediate or final necking
stations, long machine lines are assembled, all stations working simultaneously, allowing
for a high throughput. In addition to the arrangement along the main transport direction
(which is usually a horizontal direction), the stations may be stacked in order to
reduce the extension of the machine line along the main transport direction. In particular,
intermediate storage or buffer stations as well as drying stations may be arranged
above or below the other stations.
[0004] Often, the hollow articles are transported from one station to the other using a
transport chain. The chain may be provided with chain pins, whereas each pin may be
accommodated within one of the hollow articles in order to hold the respective article.
The pins are inclined with respect to a horizontal plane in order to ensure that the
articles are safely held on the chain, an angle of inclination amounts to about 2
- 15°, in particular about 6 - 8°. The inclination may be achieved by having a corresponding
design of the chain and pins, respectively, or by inclining the entire machines (including
the transport chain linking the stations) about the corresponding angle. Usual designs
of decorating sections, including base coating, printing and over varnish stations,
feature a single transport chain linking all these stations. This means that all stations
are mechanically linked, i. e. if one station is running, all stations will be running.
[0005] Usually, the different stations of the machine line are arranged in a common working
plane, the chain or chains having an operation plane which coincides or is at least
parallel with the working plane throughout the entire machine.
[0006] As mentioned, these machine lines allow for high throughput. They are especially
well suited for the production of large lots. Due to the fact that the change over
of the printing station for a new lot of hollow articles requiring a different print
image and the subsequent proofing takes considerable time, the throughput is substantially
reduced when smaller lots are processed as there is a lot of down time of the machine
line.
Summary of the invention
[0007] It is the object of the invention to create a machine pertaining to the technical
field initially mentioned, that allows for high throughput also in case of smaller
lots.
[0008] The solution of the invention is specified by the features of claim 1. According
to the invention, the machine comprises the following:
- a) at least two printing stations;
- b) at least two drying stations, a first drying station being associated to a first
of the printing stations and a second drying station being associated to a second
of the printing stations;
- c) a transport chain mechanism for transferring the hollow articles between the printing
stations and the drying stations; and
- d) a selection mechanism allowing for switching between a first mode, in which hollow
articles provided by a previous station pass through the first printing station and
the first drying station, omitting the second printing station and the second drying
station, and a second mode, in which the hollow articles pass through the second printing
station and the second drying station, omitting the first printing station and the
first drying station.
[0009] Having two independent printing stations with associated drying stations allows for
rapidly switching between using the first printer and dryer and using the second printer
and dryer. Furthermore, as both printing stations have an associated drying station,
test prints may be done on the "offline" printer during production on the "production"
(inline) printer. Thus, proofing may be effected off-line and changeover time may
be minimized or entirely spared. This substantially increases the throughput of the
machine line, especially in the case of processing smaller lots.
[0010] As a matter of course, an actual manufacturing line for cans, tubes, cartridges,
other types of containers or closures will include additional stations such as an
extrusion press, cutting, brushing and washing machines, coating machines with corresponding
dryers, a necking machine and/or a packing machine. Furthermore, buffer storage stations
(accumulators) will be arranged in between the aforementioned stations in a manner
known as such.
[0011] Preferably, the selection mechanism comprises a selector station having a first transport
chain both constituting an infeed and a first outfeed, a second transport chain constituting
a second outfeed, and a selectively engageable transfer mechanism for removing hollow
articles from the first transport chain and for feeding the removed hollow articles
to the second transport chain. In one operation mode, the hollow articles may thus
remain on the first transport chain, being essentially unaffected by the selector
station. As soon as the selection mechanism is switched to another operation mode
by engaging the transfer mechanism, the hollow articles will be removed from the first
transport chain and fed to the second transport chain. Using two separate transport
chains allows for the division of the path of the articles into two paths, furthermore,
the movement of the chains in both paths may be independently controlled. As an example,
one of the chains may be non-active or run at a manual control or test speed whereas
the other chain is running at production speed. It is preferred that the selection
mechanism is built up in such a way that the transfer mechanism may be engaged or
disengaged during production, i. e. the engagement (or disengagement) happens in between
the arrival of two subsequent articles at the transfer mechanism. This allows for
switching between one outfeed and the other without any effect on the production speed.
[0012] In a preferred embodiment, the first transport chain and the second transport chain
comprise each a U-shaped section arranged in a common operation plane, where the transfer
mechanism in its activated state cooperates with the U-shaped section of the first
transport chain for mechanically removing hollow articles fed by the first transport
chain in a lateral direction with respect to the common operation plane and for feeding
the removed hollow articles to a conveyor mechanism for feeding the removed hollow
articles to the second transport chain by moving the articles back against the lateral
direction. Accordingly, to divide the flow of articles, a side moving conveyor is
used.
[0013] The U-shaped sections may be arranged side-by-side. Alternatively, they are arranged
in a substantially vertical distance, which allows for transferring the articles by
gravitation.
[0014] As an example, the articles may be captured at the base of the U-shaped section of
the first transport chain by v-shaped baskets and moved in the lateral direction away
from the first transport chain until they are completely removed from the chain pins
of the first transport chain. During removal of the articles the baskets are moved
in the transport direction of the first transport chain at the same speed as the first
transport chain. In a next step, the baskets are moved further until the base of the
U-shaped section of the second transport chain is reached. In this section, the baskets
are moved back against the lateral direction mentioned above, and the articles are
synchronously fed to the chain pins of the second transport chain. The movements of
the baskets being synchronized to the movement of the two transport chains allows
for automatically switching between the two outfeeds without any effect on processing
speed and without any manual interaction.
[0015] It is to be noted that the operating speed of the two transport chains is required
to match as long as the hollow articles are transported from the first chain to the
second. However, if the hollow articles remain no the first chain, the second chain
may be operated by a different (in particularly lower) operating speed or even stand
still.
[0016] As an alternative to the lateral arrangement, the transport chains may be arranged
in such a way that the base of the U-shaped section may be moved down or up (in or
out of the baskets) instead of having a lateral deviation.
[0017] As an alternative, the transfer may be effected using vacuum transfer drums.
[0018] In a preferred embodiment, the transfer mechanism comprises a first drum for temporarily
accommodating hollow articles, the first drum cooperating with the first transport
chain, and a second drum for temporarily accommodating hollow articles, the second
drum cooperating with the second transport chain, wherein hollow articles accommodated
by the first drum may be selectively fed to the second drum. The drums may be vacuum
transfer drums that are known as such, that are designed and configured in such a
way that hollow articles fed by the first transport chain may be accommodated by the
first drum and transferred to the second drum and to the second transport chain in
a first mode, whereas hollow articles remain on the first transport chain in a second
mode.
[0019] The two drums may comprise carriages that are axially movable, i. e. linearly movable
along an axis that is parallel to the rotation axis of the drum. In a first axial
position, the carriages may cooperate with the transport chain cooperating with the
respective drum, in order to remove articles from the chain or to feed articles to
the chain. In a second axial position, the articles are temporarily accommodated by
the drum, independent from the respective chain.
[0020] Advantageously, at least the first drum comprises axially movable carriages for holding
hollow articles, the axial movement of the carriages being selectively controlled
by a first cam for feeding the hollow articles to the second drum or by a second cam
for keeping the hollow articles on the first transport chain. Controlling the movement
of the carriages by cams, i. e. mechanically, is a simple and mechanically stable
solution, which allows for high throughput. A switch will be provided to select between
the first cam (e. g. a cam that leads to axial displacement of the carriages in a
certain sector of the drum) and the second cam (e. g. a straight cam, keeping the
carriages in their first position).
[0021] In a preferred embodiment, the first printing station and the second printing station
are arranged in different lateral positions with respect to a main operation plane
of the transport chains. This allows for crossing the transport chains used for transporting
the articles between the stations in the two modes in a region where they run in different
operation planes and thus for a space-saving arrangement, where the printing stations
are both arranged in a first horizontal plane and the drying stations are both arranged
in a second horizontal plane, in particular above the printing stations.
[0022] In particular, a transport chain of the transport chain mechanism linking the selection
mechanism to the first printing station includes twisted sections. Employing the twisted
sections, the chain may extend out from its main operation plane into a secondary
operation plane and back into the main operation plane. This allows for transferring
the articles between two laterally offset planes without having to employ additional
lateral shifting mechanisms.
[0023] In particular, the first printing station is arranged next to the selection mechanism,
and the operation plane of the infeed chain coincides with the operation plane of
the outfeed chain of the selection mechanism. The distance between the selection mechanism
and the second printing station is larger (i. e. the second printing station is arranged
in a downstream direction of the first printing station), and the second printing
station has an operation plane of the infeed chain that is different from the operation
plane of the outfeed chain of the selection mechanism. The change of operation plane
is achieved by the twisted sections mentioned above. Due to the fact that the distance
is relatively large, a rather small inclination angle of the transport chain with
respect to the two operation planes is needed. An angle of about 4 - 8° is adequate
and may be reached by employing the twisted sections.
[0024] As an alternative to twisting, the chain may be bent. This alternative is feasible
depending on the design of the chain actually used.
[0025] Preferably, the transport chain mechanism comprises a first transport chain running
through the first printing station and the first drying station and a second transport
chain being different from the first transport chain running through the second printing
station and the second drying station. If needed, each of these transport chains may
be constituted by a number of cooperating chains. Having separate chains for each
of the printing and drying station pairs provides for higher flexibility in the product
flow, especially in the downstream direction. As an example, if a station upstream
from the selection mechanism, e. g. the drying station for the base coat, needs to
be stopped, the following stations may continue running, evacuating and further processing
the products without any product damage. Furthermore, it is possible to run one of
the printer/dryer combinations at production speed and simultaneously the other printer/dryer
combination at testing/proofing speed.
[0026] It is to be noted that the stations and transport chains will be supplemented by
a suitable number and suitably arranged buffer storage stations in a manner known
as such. These buffer storage stations provide the flexibility that is needed to account
for short-term fluctuations of the output of the upstream station as well as for short-term
fluctuations of the capacity of the downstream station.
[0027] Advantageously, the machine comprises a first manual infeed for feeding hollow articles
to the second printing station and the second drying station in the first mode and
a second manual infeed for feeding hollow articles to the first printing station and
the first drying station in the second mode. In this context, "manual infeed" relates
to an infeed that may be manually controlled on a demand basis. As a matter of course,
the feeding of the hollow articles may be effected not only manually but in addition
or exclusively by automated means. Having manual infeed for both printing and drying
stations allows for proofing parallel to the production in the first as well as in
the second mode.
[0028] Preferably, the selector station comprises a manual infeed for feeding hollow articles
to the second transport chain. In the first mode, articles received from the infeed
will remain on the first transport chain, and the second transport chain will be essentially
unaffected and its operation may be independently controlled. Accordingly, it is possible
to include a manual infeed in the selector station, using which hollow articles may
be fed to the first transport chain. Therefore, there is no need for an additional
manual infeed station for the second mode, and costs and space requirements are reduced.
[0029] Instead or in addition to manual feeding, a certain number of hollow articles may
be deviated to the printer which is in setup mode automatically by correspondingly
controlling the selector station. This will lead to a certain gap in the production
but allows for rapidly performing test prints without the need for manual feeding.
[0030] Preferably, manually infeed hollow articles are processible by the second printing
station and the second drying station in the first mode and by the first printing
station and the first drying station in the second mode, in parallel with running
production on the first printing station and the first drying station in the first
mode or on the second printing station and the second drying station in the second
mode. Accordingly, independent of the forthcoming switch between printing/drying stations,
proofing may be effected off-line, in parallel to full production.
[0031] The machine preferably comprises a takeout station for selectively singling out hollow
articles being processed by the second printing station and the second drying station
in the first mode and by the first printing station and the first drying station in
the second mode. This allows for automatically discharge sample/test print/setup/proofing
articles after drying in the respective drying station. This ensures that these articles
are not fed into the actual production run.
[0032] The takeout station may include a blower mechanism for selectively blowing out the
hollow articles to be singled out from the chain pins they are held on.
[0033] In a particularly preferable embodiment, the machine comprises the following stations:
- a) a selector station being part of the selection mechanism;
- b) the first printing station;
- c) the first drying station arranged downstream from the first printing station;
- d) a manual infeed station;
- e) the second printing station;
- f) the second drying station arranged downstream from the second printing station;
- g) a takeout station; and
- h) a merging station for feeding hollow articles processed by the first printing station
and the first drying station or the second printing station and the second drying
station, respectively, to a common outfeed.
[0034] These stations are linked to each other as follows:
i) a first outfeed of the selector station is linked to the first printing station,
j) a second outfeed of the selector station is linked to the manual infeed station,
k) the manual infeed station is linked to the second printing station,
I) outfeeds of the first drying station and the second drying station are linked to
the takeout station, and
m) the takeout station is linked to the merging station.
[0035] Two or more of the stations mentioned may be integrated into a single unit.
[0036] The merging station may be designed in such a way that the incoming transport chains
coming from the first and the second drying station, respectively, lie in two different
planes having a lateral distance from each other, and that the hollow articles fed
in from the two transport chains are moved in a lateral direction to a common outfeed
plane. In particular, the outfeed plane may correspond to one of the infeed planes
or lie in between the infeed planes. This makes a second inclined chain (with twisted
sections) unnecessary, i. e. the separation of the operation planes is achieved by
employing an inclined chain, in particular between the selection mechanism and the
second printing station, whereas the merging of the operation planes is effected locally
at the merging station.
[0037] The crossing of the two chains linking the selector station with the first printing
station and linking the selector station with the manual infeed station, respectively,
may be arranged in the region of the manual infeed station. This is where the two
chains run in different operation planes.
[0038] The manual infeed station is used for feeding test articles to the second printing
station in the first mode of the machine. In this mode, it will be possible to run
the outfeed of the manual infeed station at another speed (in particular lower speed)
than the (empty) infeed chain linking the manual infeed station to the selector station.
In the second mode of the machine articles arriving from the second outfeed of the
selector station will be forwarded to the second printing station. In this case, the
speeds of both respective chains will be identical. In the second mode, test articles
may be advantageously manually infed at the selector station, to the outfeed that
links it with the first printing station.
[0039] The selector station, the manual infeed station and the merging station may be designed
in a similar way, featuring an infeed chain and an outfeed chain both comprising a
U-shaped section, both sections being arranged in a common operation plane. They further
include a selectively engageable transfer mechanism for removing hollow articles from
the infeed chain and for feeding the removed hollow articles to the outfeed chain.
[0040] This has been described in more detail for the selector station above. When used
as the manual infeed station, the station may hand over all articles from the infeed
chain to the outfeed chain in a first operating mode, whereas in a second operating
mode, articles may be manually fed to the transfer mechanism, which will feed the
articles to the outfeed chain.
[0041] When used as the merging station, there will be two infeeds (either chains or other
means such as discharge drums) with which the transfer mechanism selectively cooperates.
Articles fed from any of the two infeeds will then be fed to the outfeed (chain).
[0042] In particular, the transfer mechanism is designed to move the articles in a lateral
direction with respect to the operation plane of the chain(s). This allows for removing
the articles from chain pins and for feeding the removed articles to the chain pins
of another chain. In the context of the merging station, this allows for merging article
flows arriving in different operation planes that are laterally spaced from each other.
[0043] Other advantageous embodiments and combinations of features come out from the detailed
description below and the totality of the claims.
Brief description of the drawings
[0044] The drawings used to explain the embodiments show:
- Fig. 1
- a block diagram of the printing section of a machine line according to the invention;
- Fig. 2
- a side view of the printing section;
- Fig. 3
- a top view showing the lower level of the printing section;
- Fig. 4
- a side view of the printing section showing the involved transport chains;
- Fig. 5A, B
- schematic side views showing the printing section in two operating modes;
- Fig. 6
- a schematic top and side view of a selector station of the embodiment;
- Fig. 7A, B
- schematic top and side views of a merging station of the embodiment in two operating
modes;
- Fig. 8A, B
- schematic front and side views of a selector station of another embodiment of the
invention.
[0045] In the figures, the same components are given the same reference symbols.
Preferred embodiments
[0046] Figure 1 is a block diagram of the printing section of a machine line according to
the invention, e. g. a machine line for the manufacture of aluminium aerosol cans.
As known from the prior art, the machine line 1 comprises a number of sections related
to different processing steps, such as a forming section, a cutting section, a coating
section, the printing section, an over varnishing section, a necking section, a packing
section etc. Each section not only comprises the respective station but auxiliary
devices such as conveyors, (buffer) storages (accumulators), dryers etc. The printing
section according to the invention and as described in the following may be used in
the context of machine lines of different configurations. In principle it may replace
prior art printing sections when down times due to the changeover of printing stations
are to be reduced.
[0047] At the entrance, receiving pre-processed articles, the printing section 100 of the
machine line 1 comprises a selector station 110. This station selectively routes the
articles to a first path 101 or to a second path 102. In the first path 101, the selector
station 110 comprises a manual inserting mechanism 111. On the first path 101, the
selector station 110 is linked to a first printing station 151 and further to a first
drying station 161. On the second path 102, the selector station 110 is linked to
a manual inserting station 140, to a second printing station 152 and further to a
second drying station 162. The output of both drying stations 161, 162 pass a takeout
station 170, where individual articles may be selectively singled out. The articles
that are not singled out at the takeout station 170 are further conveyed to a merging
station 180, where the two paths 101, 102 are merged and the articles are delivered
at a single output 181.
[0048] Figure 2 is a side view of the printing section. Figure 3 is a top view showing the
lower level of the printing section, i. e. the level of the printing stations as well
as of the selector, infeed, takeout and merging stations, including the respective
transport chains. The paths of the chains within the drying stations are not shown.
They may be chosen according to prior art designs. The Figures show in more detail
the components of the printing section 100 mentioned above, in connection with Figure
1, the main transport direction is from right to left. In particular, Figures 2 and
3 show on a lower level the selector station 110, left to which the first printing
station 151 is arranged. Again left, the manual inserting station 140 is arranged,
followed by the second printing station 152, the takeout station 170 and the merging
station 180.
[0049] In the region shown in Figures 2 and 3, the upper level features from right to left
four drying stations. The first drying station is arranged downstream of a base coating
station that does not form part of the printing section. Next, the two drying stations
161, 162 are arranged to the left, followed by a further drying station arranged downstream
of an over varnish station. Again, the latter does not form part of the printing section.
[0050] The different station and devices are linked by transport chains (cf. below, Figure
4). The stations and devices mentioned before are linked as follows: From the rightmost
drying station (which is assigned to the upstream base coating station), the articles
are fed to the infeed of the selector station 110. The selector station 110 features
two outfeeds, one of them is linked to the first printing station 151 and further
to the first drying station 161. The other outfeed of the selector station 110 is
linked to the manual inserting station 140, from there to the second printing station
152 and further to the second drying station 162. The outputs of both drying stations
161, 162 are linked with the takeout station 170 and further with the merging station
180.
[0051] It is clearly visible from Figure 3, that the transport chain 202 linking the selector
station 110 with the manual inserting station 140 deviates from the main transport
direction by an angle of about 5°, such that in the infeed region of the manual inserting
station 140 the two transport chains 202, 204 lie in two planes that are clearly separated
from each other in a lateral direction, which allows for crossing the two transport
chains in this region. The second printing station 152 lies in the plane that is defined
by the respective transport chain, i. e. it is laterally shifted with respect to the
first printing station 151. As shown in more detail below, the articles are transported
back to a single common plane in the merging station 180.
[0052] Figure 4 is a side view of the printing section showing the involved transport chains.
In order to facilitate the understanding of the Figure, the paths of the chains are
slightly simplified. Only the lower level is displayed. Where necessary, different
chains are indicated by different line styles. A first chain 202 (short-dashed) links
the drying station of the base coating station with the infeed of the selector station
110, the second outfeed of the selector station 110 and the infeed of the manual inserting
station 140. This is the chain 202 which includes a section that is inclined with
respect to the usual operation planes of the chains, namely the section linking the
second outfeed of the selector station 110 with the infeed of the manual inserting
station 140 as well as the parallel section running in the opposite direction, linking
the outfeed of the base coating drying station with the infeed of the selector station
110. In order to allow for the required change of direction, the chain 202 includes
two regions 202c, 202d, in which the chain 202 is slightly twisted (2.5° per chain
link). One of the region, namely region 202c is arranged at the upper end of a U-shaped
section constituting the infeed and the second outfeed of the selector station 110,
the other region, namely region 202d, is arranged substantially above the infeed of
the manual inserting station 140.
[0053] A further chain 203 (solid line) links the first outfeed of the selector station
110 with the infeed of the first printing station 151. Another chain 204 (solid line)
links the outfeed of the first printing station 151 with the first drying station
161 and further with the takeout station 170 and the merging station 180.
[0054] A further chain 205 (short-dashed) links the outfeed of the manual infeed station
140 with the infeed of the second printing station 152. Finally, a further chain 206
links the outfeed of the second printing station 152 with the second drying station
162 and further with the takeout station 170 and the merging station 180. As can be
seen from Figure 3, chain 204 linking the first printing station 151 with the takeout
station 170 and the merging station 180 and chains 205, 206 linking the manual inserting
station 140 with the second printing station 151 as well as the second printing station
152 with the takeout station 170 and the merging station 180 operate in parallel planes.
[0055] Figures 5A, B are schematic side views showing the printing section in two operating
modes. In the operating mode shown in Figure 5A, the first printing station is in
production mode, whereas the second printing station is available for preparation,
manual testing or proofing. In Figure 5B, the second printing station is in production
mode, whereas the first printing station is available for preparation, manual testing
or proofing. Chain segments transporting articles in production mode are indicated
by solid lines, chain segments transporting articles for testing/proofing are indicated
by dotted lines, chain segments where no articles are transported are indicated by
dashed lines.
[0056] In the first operating mode shown in Figure 5A, articles received from the drying
station of the base coating station are fed on chain 202 to the infeed of the selector
station 110. There, they are transported to the first outfeed, i. e. they are removed
from chain 202 and loaded to chain 203. Subsequently, they are transported to the
first printing station 151, taken over by chain 204 and fed to the drying station
161 associated to the first printing station 151. From the drying station 161, the
articles pass the takeout station 170 (usually unaffected) and reach the merging station
180. There, the articles are loaded onto another chain transporting the articles to
the next station. It is possible to manually feed articles in the manual inserting
station 140 (arrow 141). These manually fed articles are transported to the second
printing station 152 by chain 205; there they are taken over by chain 206 and transported
to the drying station 162 associated to the second printing station 152. From the
drying station 162, the articles are transported further to the takeout station 170.
There, all articles originating from the second printing station 152 and the associated
drying station are blown out, e. g. into a container. They may be inspected, and the
setup of the second printing station 152 may be accordingly adjusted.
[0057] In the second operating mode shown in Figure 5B, articles received from the drying
station of the base coating station are fed on chain 202 to the infeed of the selector
station 110. There, they remain unaffected, i. e. they remain on chain 202. Subsequently,
they are transported to the manual inserting station 140 where they are removed from
chain 202 and loaded to another chain 205. In this operating mode, the manual inserting
station 140 has no manual insertion purpose, but it forwards all articles to the second
printing station 152. There, the articles are taken over by chain 206 and fed to the
drying station 162 associated to the second printing station 152. From the drying
station 162, the articles pass the takeout station 170 (usually unaffected) and reach
the merging station 180. There, the articles are loaded onto another chain transporting
the articles to the next station. It is possible to manually feed articles in the
selector station 110, using the manual inserting mechanism (arrow 112). These manually
fed articles are transported to the first printing station 151 by chain 203; there
they are taken over by chain 204 and transported to the drying station 161 associated
to the first printing station 152. From the drying station 161, the articles are transported
further to the takeout station 170. There, all articles originating from the first
printing station 151 and the associated drying station are blown out, e. g. into a
container. They may be inspected, and the setup of the first printing station 151
may be accordingly adjusted.
[0058] Figure 6 is a schematic top view and a schematic side view of a selector station
of the embodiment. Two chains, namely chain 202 coming from the accumulator and linking
the selector station 110 to the second printing station, and chain 203 linking the
selector station 110 to the first printing station, run in the same operation plane
and constitute U-shaped sections, the bases of which being at the same height, slightly
above a conveyor mechanism 120. The conveyor mechanism 120 comprises v-shaped channels
that are arranged in succession and parallel to each other on a belt conveyor, the
longitudinal extension of the v-shaped channels being perpendicular to the transport
direction. The v-shaped channels are movable along their longitudinal extension and
have annular end faces, such that they may engage the articles 2 held on the pins
202a, 203a of the chains 202, 203 and transport them in transport direction as well
as in a perpendicular direction thereto.
[0059] The movement of the v-shaped channels may be controlled e. g. by selectively engageable
cams or by using servo controls. In Figure 6, the transport path 121 defined by the
movement of the v-shaped channels is schematically indicated. In the mode shown in
Figure 6, the articles 2 transported on the incoming chain 202 are not affected by
the selector station 110, i. e. the situation corresponds to the second operating
mode as discussed above. Articles 2 may be manually fed to the v-shaped channels,
in a feeding region 122. The channels move laterally and push the articles 2 onto
the pins 203a of the first outfeed chain 203. In this mode, the conveyor mechanism
120 and the first outfeed chain 203 may be operated at a speed that is different from
the operating speed of the chain 202 coming from the accumulator.
[0060] In the first mode (not shown), the articles 2 fed on chain 202 are grasped by the
v-shaped channels, removed by lateral movement of the channels and fed back to first
outfeed chain 203. Both chains and the conveyor mechanism 120 will run at the same
operating speed and synchronized to each other.
[0061] Figures 7A, B are schematic top and side views of a merging station 180 of the embodiment
in two operating modes. In Figure 7A, processed articles are taken over from the first
printing station, whereas in Figure 7B, processed articles are taken over from the
second printing station.
[0062] The articles 2 are fed on one of two discharge drums 182, 183, articles 2 coming
from the first drying station associated with the first printing station are fed to
drum 182, whereas articles 2 coming from the second drying station associated with
the second printing station are fed to drum 183. Due to the fact that in both modes
all articles coming from one of the printing stations are blown out at the preceding
takeout station, articles 2 will always arrive only at one of the two drums 182, 183.
A chain 207 constitutes a U-shaped section, the bases of which being at the same height,
slightly above a conveyor mechanism 184. The transport plane of the chain 207 corresponds
to the transport plane of the first drum 182.
[0063] Again, the conveyor mechanism 184 comprises v-shaped channels that are arranged in
succession and parallel to each other on a belt conveyor, the longitudinal extension
of the v-shaped channels being perpendicular to the transport direction. The v-shaped
channels are movable along their longitudinal extension and may accommodate articles
delivered on either the first drum 182 or the second drum 183, depending on their
lateral position in the region of the drums 182, 183. They may transport them in transport
direction as well as in a perpendicular direction thereto.
[0064] The movement of the v-shaped channels may be controlled e. g. by selectively engageable
cams or by using servo controls. The transport paths 185, 186 defined by the movement
of the v-shaped channels are schematically indicated in Figures 7A, 7B.
[0065] In the first operating mode according to Figure 7A, the articles arrive on the first
drum 182. They are taken over from the v-shaped channels of the conveyor mechanism
184, are transported simultaneously in the transport direction and in a lateral direction,
away from the first drum 182. In a second phase, the channels move back laterally
and push the articles 2 onto the pins 207a of the chain 207.
[0066] In the second operating mode according to Figure 7B, the articles arrive on the second
drum 183. They are taken over from the v-shaped channels of the conveyor mechanism
184, are transported in the transport direction in a first phase. In a second phase,
the channels move back laterally and push the articles 2 onto the pins 207a of the
chain 207.
[0067] Apparently, the selector station 120 shown in Figure 6 is very similar to the merging
station 180 shown in Figures 7A, 7B. Another very similar station is the manual inserting
station 140 shown e. g. in Figures 2 and 4. In principle, it corresponds to the selector
station 120. In the first operating mode, the manual inserting station 140 is used
for manual insertion of articles. Accordingly, it will be configured just like the
selector station 120 in Figure 6. In the second operating mode, the manual inserting
station 140 forwards all articles to the second printing station. Accordingly, it
will be configured similar to the configuration of the merging station 180 shown in
Figure 7A, i. e. the articles will be removed by the conveyor mechanism from the incoming
chain 202 and pushed on to the pins of outgoing chain 205.
[0068] The Figures 8A, 8B are schematic front and side views of a selector station of another
embodiment of the invention. It may be used in place of the selector station 110 described
above, in connection with Figure 6. Again, a very similar station may be used in place
of the merging station 180 described above, in connection with Figure 7. The remaining
components of the printing section, including the transport chains and the layout
of the stations, may remain unchanged.
[0069] Two chains, namely chain 202 coming from the accumulator and linking the selector
station 310 to the second printing station, and chain 203 linking the selector station
310 to the first printing station, run in the same operation plane and constitute
U-shaped sections, running along a section of the circumference of two vacuum drums
311, 312. The plane defined by the chains 202, 203 coincides with the back end of
the drums 311, 312, the pins holding the articles have an axial direction, i. e. extend
parallel to the rotation axes of the drums 311, 312 pointing to the front surface
of the drums 311, 312. As described above, the chains 202, 203 and accordingly the
drums 311, 312 include a slight angle with a vertical plane in order to ensure that
the articles are safely held on the pins of the chains 202, 203.
[0070] Carriages 311a, 312a are supported on the drums in such a way that they are movable
in an axial direction. Depending on their rotational position the axial position is
controlled by a cam, the carriages 311 a, 312a may be displaced from a position A,
in which they cooperate with the respective chain 202, 203 to a position B, in which
the articles are released from the respective chain 202, 203. In a first mode, in
which the articles are to be handed over from chain 202 to chain 203, displayed in
Figure 8B, the articles released from the chain 202 will be transferred by gravity
from the first vacuum drum 311 to the second vacuum drum 312 in a region which is
close to the smallest distance of the two vacuum drums 311, 312 (cf. arrow 313).
[0071] In a second mode, selectable by changing a mechanical switch, such that the carriages
311 a of the first vacuum drum 311 are controlled by a different (straight) cam, the
carriages will retain their axial position, which means that the articles remain on
the first transport chain 202 and will be transported to the second printing station.
[0072] In this embodiment, manual feeding of articles will be effected on the chain loop
just after the respective vacuum drum 311, 312.
[0073] If a similar station is used for merging articles coming from the first drying station
associated with the first printing station and articles coming from the second drying
station associated with the second printing station, two respective incoming vacuum
drums (that may be in different planes) may cooperate with a single outgoing vacuum
drum. The carriages of the outgoing vacuum drum will be controlled in such a way that
articles may be received from the respective incoming drum. Again, control of the
carriages may be effected by different cams, and a mechanical switch may be provided
to select the appropriate cam.
[0074] The invention is not limited to the described embodiments. In particular the specific
arrangement of the stations and the build-up of the individual stations may be different.
Additional station, in particular accumulators, may be arranged in between the described
stations. In summary, it is to be noted that the invention provides a machine for
printing hollow articles such as cans, tubes, cartridges or other types of containers
that allows for high throughput also in case of smaller lots.
1. A machine for printing hollow articles, comprising:
a) at least two printing stations;
b) at least two drying stations, a first drying station being associated to a first
of the printing stations and a second drying station being associated to a second
of the printing stations;
c) a transport chain mechanism for transferring the hollow articles between the printing
stations and the drying stations; and
d) a selection mechanism allowing for switching between a first mode, in which hollow
articles provided by a previous station pass through the first printing station and
the first drying station, omitting the second printing station and the second drying
station, and a second mode, in which the hollow articles pass through the second printing
station and the second drying station, omitting the first printing station and the
first drying station.
2. The machine as recited in claim 1, characterized in that the selection mechanism comprises a selector station having a first transport chain
constituting an infeed and a first outfeed, a second transport chain constituting
a second outfeed, and a selectively engageable transfer mechanism for removing hollow
articles from the first transport chain and for feeding the removed hollow articles
to the second transport chain.
3. The machine as recited in claim 2, characterized in that the first transport chain and the second transport chain comprise each a U-shaped
section arranged in a common operation plane, where the transfer mechanism in its
activated state cooperates with the U-shaped section of the first transport chain
for mechanically removing hollow articles fed by the first transport chain in a lateral
direction with respect to the common operation plane and for feeding the removed hollow
articles to a conveyor mechanism for feeding the removed hollow articles to the second
transport chain by moving the articles back against the lateral direction.
4. The machine as recited in claim 3, characterized in that the transfer mechanism comprises a first drum for temporarily accommodating hollow
articles, the first drum cooperating with the first transport chain, and a second
drum for temporarily accommodating hollow articles, the second drum cooperating with
the second transport chain, wherein hollow articles accommodated by the first drum
may be selectively fed to the second drum.
5. The machine as recited in claim 4, characterized in that at least the first drum comprises axially movable carriages for holding hollow articles,
the axial movement of the carriages being selectively controlled by a first cam for
feeding the hollow articles to the second drum or by a second cam for keeping the
hollow articles on the first transport chain.
6. The machine as recited in any of claims 1 to 5, characterized in that the first printing station and the second printing station are arranged in different
lateral positions with respect to a main operation plane of the transport chains.
7. The machine as recited in claim 6, characterized in that a transport chain of the transport chain mechanism linking the selection mechanism
to the first printing station includes twisted sections.
8. The machine as recited in any of claims 1 to 7, characterized in that the transport chain mechanism comprises a first transport chain running through the
first printing station and the first drying station and a second transport chain being
different from the first transport chain running through the second printing station
and the second drying station.
9. The machine as recited in any of claims 1 to 8, comprising a first manual infeed for
feeding hollow articles to the second printing station and the second drying station
in the first mode and a second manual infeed for feeding hollow articles to the first
printing station and the first drying station in the second mode.
10. The machine as recited in one of claims 2 to 5 and claim 7, characterized in that the selector station comprises a manual infeed for feeding hollow articles to the
second transport chain.
11. The machine as recited in claims 9 or 10, characterized in that manually infed hollow articles are processible by the second printing station and
the second drying station in the first mode and a by the first printing station and
the first drying station in the second mode, in parallel with running production on
the first printing station and the first drying station in the first mode or on the
second printing station and the second drying station in the second mode.
12. The machine as recited in claim 11, characterized by a takeout station for selectively singling out hollow articles being processed by
the second printing station and the second drying station in the first mode and a
by the first printing station and the first drying station in the second mode.
13. The machine as recited in any of claims 1 to 12,
characterized by
a) a selector station being part of the selection mechanism;
b) the first printing station;
c) the first drying station arranged downstream from the first printing station;
d) a manual infeed station;
e) the second printing station;
f) the second drying station arranged downstream from the second printing station;
g) a takeout station; and
h) a merging station for feeding hollow articles processed by the first printing station
and the first drying station or the second printing station and the second drying
station, respectively, to a common outfeed,
where
i) a first outfeed of the selector station is linked to the first printing station,
j) a second outfeed of the selector station is linked to the manual infeed station,
k) the manual infeed station is linked to the second printing station,
I) outfeeds of the first drying station and the second drying station are linked to
the takeout station, and
m) the takeout station is linked to the merging station.