Title: Deformation of thin walled bodies
Abstract: A thin walled body such as a container is gripped at a holding station and tooling is engaged to deform the wall of the body at a predetermined zone. The predetermined wall zone is co-aligned with the tooling by means of co-ordinated movement of the tooling (typically by means of rotation about a tooling axis) prior to engagement with the wall zone.
Patent Number: 7,024,912 Issued on 04/11/2006 to Campo, et al.
| Inventors:
|
Campo; Santiago Garcia (Llodio, ES);
Goiria; Juan Salz (Llodia, ES)
|
| Assignee:
|
Envases (UK) Limited (Port Talbot, GB)
|
| Appl. No.:
|
851919 |
| Filed:
|
May 21, 2004 |
Foreign Application Priority Data
| Feb 10, 2000[GB] | 0003033 |
| Oct 27, 2000[GB] | 0026325 |
| Current U.S. Class: |
72/414; 72/421; 72/447; 72/715; 72/379.4 |
| Current Intern'l Class: |
B21D 17/02 (20060101) |
| Field of Search: |
72/173,91,94,102,105,120,117,347,370.08,379.4,414,441, 447,421,715,420,446
|
References Cited [Referenced By]
U.S. Patent Documents
| 2966872 | Jan., 1961 | Schmocker.
| |
| 3247548 | Apr., 1966 | Fields et al.
| |
| 3628451 | Dec., 1971 | McClellan et al.
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| 3687098 | Aug., 1972 | Maytag.
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| 3688537 | Sep., 1972 | Schneider.
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| 3967488 | Jul., 1976 | Hasselbeck et al.
| |
| 4070888 | Jan., 1978 | Gombas.
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| 4120190 | Oct., 1978 | Schlau et al.
| |
| 4341103 | Jul., 1982 | Escallon et al.
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| 4487048 | Dec., 1984 | Frei.
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| 4625541 | Dec., 1986 | Jones et al.
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| 4723430 | Feb., 1988 | Hahn.
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| 5341667 | Aug., 1994 | Lee, Jr.
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| 5467628 | Nov., 1995 | Bowlin et al.
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| 5727414 | Mar., 1998 | Halasz et al.
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| 5761942 | Jun., 1998 | Johnson et al.
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| 5799525 | Sep., 1998 | Johnson et al.
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| 5893286 | Apr., 1999 | Johnson et al.
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| 5916317 | Jun., 1999 | Willoughby et al.
| |
| 5941109 | Aug., 1999 | Johnson et al.
| |
| 6009733 | Jan., 2000 | Cheers et al.
| |
| 6338263 | Jan., 2002 | Obata et al.
| |
| Foreign Patent Documents |
| 1214991 | Dec., 2001 | EP.
| |
| 1214994 | Dec., 2001 | EP.
| |
| 778545 | Jul., 1957 | GB.
| |
| 1384184 | Feb., 1975 | GB.
| |
| 1408091 | Oct., 1975 | GB.
| |
| WO 97/2150/5 | Nov., 1996 | WO.
| |
| WO 98/0328/0 | Jul., 1997 | WO.
| |
Primary Examiner: Tolan; Ed
Attorney, Agent or Firm: Gordon & Jacobson, P.C.
Parent Case Text
This application is a continuation of U.S. patent application Ser. No. 10/182,643,
filed Sep. 30, 2002, which is a national stage of International Application No.
PCT/GB01/00526, filed Feb. 9, 2001.
Claims
The invention claimed is:
1. Apparatus for use in deforming a predetermined wall zone of a thin wall of
a container, the apparatus comprising:
i) a tooling arrangement comprising internal tooling to be positioned in an interior
space defined by the container and external tooling to be positioned in an exterior
space defined by the container, the internal tooling being moveable relative to
the wall of the container;
a first tooling configuration in which the internal tooling can be inserted into
or retracted from the interior space defined by the container; and
a second wall engaging configuration for effecting deforming of the predetermined
wall zone; and
ii) a reorientation arrangement to rotationally co-align the container with respect
to the internal and external tooling for deformation of the predetermined wall zone;
wherein the reorientation arrangement is first operable to rotationally co-align
the container with respect to the internal and external tooling, and, with the
internal and external tooling and container in a fixed rotational orientation,
the predetermined wall zone of the container is deformed between the internal and
external tooling, the internal and external tooling moving translationally only
without rotation from the first configuration to the second wall engaging configuration
to thereby effect deformation at the predetermined wall zone.
2. Apparatus according to claim 1, wherein the internal tooling is expandable
between the first and second wall engaging configurations.
3. Apparatus according to claim 1, wherein the internal tooling is movable toward
or away from the axis of the container between the first and second wall engaging configurations.
4. A method of deforming a thin walled container at a predetermined wall zone comprising:
providing a tooling arrangement comprising internal tooling to be positioned
in an interior space defined by the container and external tooling to be positioned
in an exterior space defined by the container;
rotationally co-aligning the container with the internal and external tooling;
with the container and the internal and external tooling in a fixed rotational orientation;
i) advancing the internal and external tooling arranged in a first configuration
such that the internal tooling enters the interior space defined by the container
and the external tooling is positioned adjacent and exterior to the predetermined
wall zone of the container; and
ii) moving the internal and external tooling to a second wall engaging configuration
for effecting deforming of the predetermined wall zone, wherein the internal and
external tooling moves translationally only without rotation to the second wall
engaging configuration.
5. A method according to claim 4, wherein in reconfiguration of the internal
and external tooling between the first and second wall engaging configurations,
the internal tooling is expanded.
6. A method according to claim 4, wherein the internal tooling cooperates with
the external tooling to effect deformation of the predetermined wall zone.
7. A method according to claim 4, wherein the container is supported in a holding
station during the deforming of the predetermined wall zone, the tooling being
provided at a separate tooling station.
8. Apparatus for use in deforming a predetermined wall zone of a thin wall of
a container, the apparatus comprising:
an internal tooling part to be positioned in an interior space defined by the container;
an external tooling part to be positioned in an exterior space defined by the container;
a co-alignment arrangement, operable to co-align the container with the internal
and external tooling parts before deformation of the wall zone;
wherein the external and internal tooling parts co-operate in a forming operation
to deform the predetermined wall zone of the container therebetween, wherein the
internal tooling part is moveable relative to the wall of the container between
a first tooling configuration in which the internal tooling part can be inserted
or retracted from the interior space defined by the container, to a second tooling
configuration in which the internal tooling part is positioned closely adjacent
or engaging the interior container wall at the predetermined wall zone for effecting
deformation of the predetermined wall zone; and
wherein the external and internal tool parts are configured to effect deformation
of a plurality of predetermined discrete zones spaced on opposed sides of the container
in the same operation.
9. Apparatus according to claim 8, further comprising:
wedge or cam actuators arranged to effect movement of the internal and external
tooling parts toward or away from the container wall.
10. A method for deforming a plurality of predetermined discrete wall zones of
a thin wall of a container, the apparatus comprising:
providing a tooling arrangement comprising an internal tooling part to be positioned
in an interior space defined by the container and an external tooling part to be
positioned in an exterior space defined by the container;
aligning the container with the internal and external tooling parts before deforming
the plurality of predetermined discrete wall zones;
deforming the plurality of predetermined discrete wall zones in a single operation
by moving the internal tooling part between a first tooling configuration in which
the internal tooling part can be inserted or retracted from the interior space
defined by the container, to a second tooling configuration in which the internal
tooling part is positioned closely adjacent or engaging the interior container
wall at the plurality of predetermined wall zone, wherein the external and internal
tool parts are configured to effect deformation of the plurality of predetermined
discrete zones spaced on opposed sides of the container.
11. A method according to claim 10, wherein, in moving the internal tooling between
the first and second tooling configurations, the internal tooling is expanded.
Description
The present invention relates to deformation of generally thin walled bodies,
particularly thin walled containers or tube-form bodies which may be of cylindrical
or other form.
The invention is particularly suited to embossing of thin walled metallic bodies
(particularly aluminium containers) by embossing or the like. More specifically
the invention may be used in processes such as registered embossing of thin walled
bodies, particularly registered embossing of containers having pre-applied (pre-printed)
surface decoration.
It is known to be desirable to deform by embossing or the like the external cylindrical
walls of metallic containers such as aluminium containers. In particular attempts
have been made to emboss the walls of containers at predetermined locations to
complement a printed design on the external surface of such a container. In such
techniques it is important to coordinate the embossing tooling with the preprinted
design on the container wall.
Prior art proposals disclose the use of a scanning system to identify the position
of the container relative to a datum position and reorientation of the container
to conform to the datum position.
Prior art embossing techniques and apparatus are disclosed in, for example,
WO-A-9803280, WO-A-9803279, WO-A-9721505 and WO-A-9515227. Commonly in such techniques
the container is loaded into an internal tool which acts to support the container
and also co-operate with an external tool in order to effect embossing. Such systems
have disadvantages, as will become apparent from the following.
An improved technique has now been devised.
According to a first aspect, the present invention provides a method of
deforming a thin walled body, the method comprising:
- i) holding the body gripped securely at a holding station;
- ii) engaging tooling to deform the wall of the body at a predetermined
wall zone, the tooling being provided at a tooling station which is adjacent the
holding station during deformation;
- wherein the predetermined wall zone is co-aligned with the tooling by
means of co-ordinated movement of the tooling prior to deforming engagement with
the wall of the body.
According to a further aspect, the invention provides apparatus for deforming
a thin walled body, the apparatus including:
- i) a holding station for holding the body gripped securely;
- ii) a tooling station including tooling to deform the body at a predetermined
wall zone of the body, the tooling station being positioned at a location adjacent
the holding station during deformation;
- iii) determination means for determining the orientation of the cylindrical
body relative to a reference (datum) situation;
- iv) means for co-ordinated movement to reconfigure the tooling to co-align
with the predetermined wall zone prior to deforming engagement of the tooling with
the body.
Co-alignment of the tooling and the wall zone of the body is typically
required in order to ensure that embossing deformation accurately lines up with
pre-printed decoration on the body. In the technique of the present invention,
the body is not passed from being supported at a holding station to being supported
by the tooling but, by contrast, remains supported at the holding station throughout
the deforming process.
Re-configuration of the tooling avoids the requirement for the or
each holding or clamping station to have the facility to re-orientate a respective body.
The technique is particularly suited to embossing containers having wall thicknesses(t)
in the range 0.25 mm to 0.8 mm (particularly in the range 0.35 mm to 0.6 mm). The
technique is applicable to containers of aluminium including alloys, steel, tinplate
steel, internally polymer laminated or lacquered metallic containers, or containers
of other materials. Typically the containers will be cylindrical and the deformed
embossed zone will be co-ordinated with a pre-printed/pre-applied design on the
circumferential walls. Typical diameters of containers with which the invention
is concerned will be in the range 35 mm to 74 mm although containers of diameters
outside this range are also susceptible to the invention.
Beneficially the tooling will be re-configurable by rotation of the
tooling about a rotational tooling axis to co-align with the predetermined wall zone.
The determination means preferably dictates the operation of the tooling rotation
means to move/rotate the tooling to the datum position. The determination means
preferably determines a shortest rotational path (clockwise or anti-clockwise)
to the datum position and triggers rotation of the tooling in the appropriate sense.
The length of time available to perform the steps of re-orientation and deformation
is relatively short for typical production runs which may process bodies at speeds
of up to 200 containers per minute. Re-orientation of the tooling (particularly
by rotation of the tooling about an axis) enables the desired re-orientation to
be achieved in the limited time available. The facility to re-orientate clockwise
or anti-clockwise following sensing of the container orientation and shortest route
to the datum position is particularly advantageous in achieving the process duration
times required.
According to a further aspect, the invention provides apparatus for use
in deforming a wall zone of a thin walled container, the apparatus comprising internal
tooling to be positioned internally of the container, and external tooling to be
positioned externally of the container, the external and internal tooling co-operating
in a forming operation to deform the wall zone of the container, the internal tooling
being moveable toward and away from the centreline or axis of the container between
a retraction/insertion tooling configuration in which the internal tool can be
inserted or retracted from the interior of the container, to a wall engaging configuration
for effecting deforming of the wall zone.
Correspondingly a further aspect of the invention provides a method
of deforming a thin walled container, the method comprising:
- inserting internal tooling into the interior of the container, the internal
tooling being in a first, insertion configuration for insertion;
- moving the tooling to a second, (preferably expanded) position or configuration
closely adjacent or engaging the internal container wall so as to facilitate deformation
of a wall zone of the container;
- returning the tooling from the second position toward the first tooling
configuration thereby to permit retraction of the internal tooling from the container.
Because the internal tooling is movable toward and away from the container
wall (preferably toward and away from the axis/centreline of the container), embossed
relief features of greater depth/height can be produced. This is because prior
art techniques generally use an internal tool which also serves to hold the container
during deformation (embossing) and therefore typically only slight clearance between
the internal tool diameter and the internal diameter of the container has been
the standard practice.
In accordance with the broadest aspect of the invention, the relief pattern for
embossing may be carried on cam portions of internal and/or external tools, the
eccentric rotation causing the cam portions to matingly emboss the relevant portion
of the container wall.
A particular benefit of the present invention is that it enables a greater area
of the container wall (greater dimension in the circumferential direction) to be
embossed than is possible with prior art techniques where the emboss design would
need to be present on a smaller area of the tool. Rotating/cam-form tooling, for
example, has the disadvantage of having only a small potential area for design embossing.
Re-configurable, particularly collapsible/expandable internal tooling
provides that greater depth/height embossing formations can be provided, the internal
tooling being collapsed from engagement with the embossed zone and subsequently
retracted axially from the interior of the container.
Embossed feature depth/height dimensions in the range 0.5 mm and above (even
0.6 mm to 1.2 mm and above) are possible which have not been achievable with prior
art techniques.
According to a further aspect, the invention provides apparatus for use
in deforming the cylindrical wall of a thin walled cylindrical container, the apparatus
comprising an internal tooling part to be positioned internally of the container,
and an external tooling part to be positioned externally of the container, the
external and internal tools co-operating in a forming operation to deform a portion
of the cylindrical container wall therebetween; wherein tooling actuation means
is provided such that:
- (a) the external and internal tools are movable independently of one
another to deform the container wall; and/or
- (b) deforming force applied to the external and internal tools is positioned
at force action zones spaced at opposed sides of the zone of the container wall
to be deformed.
As described above, the technique of the invention is particularly suited to
embossing
containers having relatively thick wall thickness dimensions (for example in the
range 0.35 mm to 0.8 mm). Such thick walled cans are suitable for containing pressurised
aerosol consumable products stored at relatively high pressures. Prior art techniques
have not been found to be suitable to successfully emboss such thicker containers,
nor to produce the aesthetically pleasing larger dimensioned emboss features as
is capable with the present invention (typically in the range 0.3 mm to 1.2 mm depth/height).
The technique has also made it possible to emboss containers (such as seamless
monobloc aluminium containers) provided with protective/anti-corrosive internal
coatings or layers without damage to the internal coating or layer.
According to a further aspect, the invention therefore provides an embossed
container or tube-form product, the product comprising a product side-wall having
a thickness substantially in the range 0.25 mm to 0.8 mm and a registered embossed
wall zone, the embossed deformation having an emboss form depth/height dimension
substantially in the range 0.3 mm to 1.2 mm or above.
Preferred features of the invention are defined in the appended claims
and readily apparent from the following description. The various features identified
and defined as separate aspects herein are also mutually beneficial and may be
beneficially included in combination with one another.
The invention will now be further described in a specific embodiment, by way
of example only, and with reference to the accompanying drawings, in which:
FIG. 1 is a flow diagram of a process according to the invention;
FIG. 2 is a view of a container to be operated upon in accordance with the invention;
FIG. 3 is a side view of the container of FIG. 2 in a finish formed state;
FIG. 4 is a 360 degree view of a positional code in accordance with the invention;
FIG. 5 is a schematic side view of apparatus in accordance with the invention;
FIGS. 6 and 7 are half plan views of apparatus components of FIG. 5;
FIGS. 8, 9 and 10 correspond to the views of FIGS. 5, 6
and 7 with components in a different operational orientation;
FIG. 11 is a schematic close up sectional view of the apparatus of the preceding
figures in a first stage of the forming process;
FIG. 11
a is a detail view of the forming tools and the container wall
in the stage of operation of FIG. 11;
FIGS. 12, 12
a to 16, 16
a correspond to the
views of FIGS. 11 and 11
a; and
FIG. 17 is a schematic sectional view of an embossed zone of a container wall
in accordance with the invention.
Referring to the drawings the apparatus and technique is directed to plastically
deforming (embossing or debossing) the circumferential wall of an aluminium container
1 at a predetermined position relative to a preprinted decorative design
on the external container wall. Where the embossing deformation is intended to
coincide with the printed decorative design, this is referred to in the art as
Registered Embossing.
In the embodiment shown in the drawings, a design
50 comprising a series
of three axially spaced arc grooves is to be embossed at 180 degree opposed locations
on the container wall (see FIG. 16
a). For aesthetic reasons it is important
that the location at which the design
50 is embossed is coordinated with
the printed design on the container
1 wall. Coordination of the container
1 axial orientation with the tooling to effect deformation is therefore crucial.
Referring to FIGS. 5 to 7 the forming apparatus
2 comprises a vertically
orientated rotary table
3 operated to rotate (about a horizontal axis) in
an indexed fashion to successively rotationally advanced locations. Spaced around
the periphery of table
3 are a series of container holding stations comprising
clamping chucks
4. Containers are delivered in sequence to the table in
random axial orientations, each being received in a respective chuck
4,
securely clamped about the container base
5.
A vertically orientated forming table
6 faces the rotary table
3
and carries a series of deformation tools at spaced tooling stations
7.
Following successive rotary index movements of rotary table
3, table
6
is advanced from a retracted position (FIG. 5) to an advanced position (FIG. 8).
In moving to the advanced position the respective tools at tooling stations
7
perform forming operations on the container circumferential walls proximate their
respective open ends
8. Successive tooling stations
7 perform successive
degrees of deformation in the process.
This process is well known and used in the prior art and is frequently known
as necking. Necked designs of various neck/shoulder profiles such as that shown
in FIG. 3 can be produced.
Necking apparatus typically operates at speeds of up to 200 containers per
minute giving a typical working time duration at each forming station in the order
of 0.3 seconds. In this time, it is required that the tooling table
6 moves
axially to the advanced position, the tooling at a respective station contacts
a respective container and deforms one stage in the necking process, and the tooling
table
6 is retracted.
In accordance with the invention, in addition to the necking/shoulder-forming
tooling at stations
7, the tooling table carries embossing toling
10
at an embossing station
9. The embossing tooling (shown most clearly in
FIGS. 11 to 16) comprises inner forming tool parts
11a,
11b
of respective arms
11 of an expandible internal tool mandrel
15.
Tool parts
11a,
11b carry respective female embossing
formations
12.
The embossing tooling
10 also includes a respective outer tool arrangement
including respective arms
13 carrying tooling parts
13a,
13b
having complementary male embossing formations
14. In moving to the
table
7 advanced position the respective internal tool parts
11a,
11b are positioned internally of the container spaced adjacently
the container
1 wall; the respective external tool parts
13a,
13b are positioned externally of the container spaced adjacently
the container
1 wall.
The internal mandrel
15 is expandible to move the tooling parts
11a,
11b to a relatively spaced apart position in which they abut the
internal wall of the container
1 (see FIG. 12) from the collapsed position
shown in FIG. 11 (tools
11a,
11b spaced from the internal
wall of the container
1). An elongate actuator rod
16 is movable
in a longitudinal direction to effect expansion and contraction of the mandrel
15 and consequent movement apart and toward one another of the tool parts
11a,
11b. A the cam head portion
17 of the actuator
rod
16 effects expansion of the mandrel
15 as the actuator rod
16
moves in the direction of arrow A. The cam head portion
17 acts against
sloping wedge surfaces
65 of the tool parts
11a,
11b
to cause expansion (moving apart) of the tool parts
11a,
11b.
The resilience of arms
11 biases the mandrel
15 to the closed position
as the rod
16 moves in the direction of arrow B.
Outer tool arms
13 are movable toward and away from one another under
the influence of closing cam arms
20 of actuator
21 acting on a cam
shoulder
13c of respective arms
13. Movement of actuator
21
in the direction of arrow D causes the external tooling parts
13a to
be drawn toward one another. Movement of actuator
21 in the direction of
arrow E causes the external tool parts
13a to relatively separate.
Arms
13 and
11 of the outer tool arrangement and the inner mandrel
are retained by cam support ring
22. The arms
11,
13 resiliently
flex relative to the support ring
22 as the actuators
21,
16 operate.
As an alternative to the cam/wedge actuation arrangement, other actuators may
be used such as hydraulic/pneumatic, electromagnetic (e.g. solenoid actuators)
electrical is (servo/stepping) motors.
The operation of the embossing tooling is such that the internal mandrel
15
is operable to expand and contract independently of the operation of the external
tool parts
13a.
The internal mandrel
15 (comprising arms
11) and the external tooling
(comprising arms
13) connected at cam support ring
22, are rotatable
relative to table
6, in unison about the axis of mandrel
15. Bearings
25 are provided for this purpose. A servo-motor (or stepping motor)
26
is connected via appropriate gearing to effect controlled rotation of the tooling
10 relative to table
6 in a manner that will be explained in detail later.
With the tooling
10 in the position shown in FIG. 11, the mandrel
15
is expanded by moving actuator rod
16 in the direction of arrow A causing
the internal tooling parts
11a to lie against the internal circumferential
wall of cylinder
1, adopting the configuration shown in FIGS. 12,
12a.
Next actuator
21 moves in the direction of arrow D causing cam arms
20
to act on cam shoulder
13c and flexing arms
13 toward one
another. In so doing the external tooling parts
13a engage the cylindrical
wall of container
1, projections
14 deforming the material of the
container
1 wall into respective complementary receiving formations
12
on the internal tooling parts
11a.
The deforming tooling parts
11a,
13a, can be hard,
tool steel components or formed of other materials. In certain embodiments one
or other of the tooling parts may comprise a conformable material such as plastics,
polymeric material or the like.
An important feature is that the internal tooling parts
11a support
the non deforming parts of the container wall during deformation to form the embossed
pattern
50. At this stage in the procedure, the situation is as shown in
FIGS. 13,
13a. The configuration and arrangement of the cam arms
20, cam shoulders
13c of the external embossing tooling and
the sloping (or wedge) cam surface of internal tooling parts
11a (cooperating
with the cam head
17 of rod
16) provide that the embossing force
characteristics of the arrangement can be controlled to ensure even embossing over
the entire area of the embossed pattern
50. The external cam force action
on the outer tool parts
13a is rearward of the embossing formations
14; the internal cam force action on the inner tool parts
11a
is forward of the embossing formations
12. The forces balance out to
provide a final embossed pattern of consistent depth formations over the entire
zone of the embossed pattern
50.
Next actuator
21 returns to its start position (arrow E) permitting the
arms
13 of the external toling to flex outwardly to their normal position.
In so doing tooling parts
13a disengage from embossing engagement
with the container
1 external surface. At this stage in the procedure, the
situation is as shown in FIGS. 14,
14a.
The next stage in the procedure is for the internal mandrel to collapse moving
tooling parts
11a out of abutment with the internal wall of the cylinder
1. At this stage in the procedure, the situation is as shown in FIGS. 15,
15a.
Finally the tooling table
6 is retracted away from the rotatable table
3 withdrawing the tooling
10 from the container. At this stage in
the procedure, the situation is as shown in FIGS. 16,
16a.
In the embodiment described, the movement of the tools to effect embossing is
translational only. It is however feasible to utilise rotational external/internal
embossing tooling as is known generally in the prior art.
The rotary table is then indexed rotationally moving the embossed container to
adjacent with the next tooling station
7, and bringing a fresh container
into alignment with the embossing tooling
10 at station
9.
The embossing stages described correspond to stages
106 to
112
in the flow diagram of FIG. 1.
Prior to the approachment of the embossing tooling
10 to a container
1 clamped at table
3 (FIG. 11 and stage
106 of FIG. 1) it
is important that the container
1 and tooling
10 are accurately rotationally
oriented to ensure that the embossed pattern
50 is accurately positioned
with respect to the printed design on the exterior of the container.
According to the present invention this is conveniently achieved by reviewing
the position of a respective container
1 whilst already securely clamped
in a chuck
4 of the rotary table
3, and rotationally reorientating
the embossing tooling
10 to the required position. This technique is particularly
convenient and advantageous because a rotational drive of one arrangement (the
embossing tooling
10) only is required. Chucks
4 can be fixed relative
to the table
3 and receive containers in random axial rotational orientations.
Moving parts for the apparatus are therefore minimised in number, and reliability
of the apparatus is optimised.
The open ends
8 of undeformed containers
1 approaching the apparatus
2 have margins
30 printed with a coded marking band
31 comprising
a series of spaced code blocks or strings
32 (shown most clearly in FIG.
4). Each code block/string
32 comprises a column of six data point zones
coloured dark or light according to a predetermined sequence.
With the container
1 clamped in random orientation in a respective chuck
4 a charge coupled device (CCD) camera
60 views a portion of the
code in its field of view. The data corresponding to the viewed code is compared
with the data stored in a memory (of controller
70) for the coded band and
the position of the can relative to a datum position is ascertained. The degree
of rotational realignment required for the embossing tooling
10 to conform
to the datum for the respective container is stored in the memory of main apparatus
controller
70. When the respective container
10 is indexed to face
the embossing tooling
10 the controller instigates rotational repositioning
of the tooling
10 to ensure that embossing occurs at the correct zone on
the circumferential surface of the container
1. The controller
70
when assessing the angular position of the tooling relative to the angular position
to be embossed on the container utilises a decision making routine to decide whether
clockwise or counterclockwise rotation of the tooling
10 provides the shortest
route to the datum position, and initiates the required sense of rotation of servo-motor
26 accordingly. This is an important feature of the system in enabling rotation
of the tooling to be effected in a short enough time-frame to be accommodated within
the indexing interval of the rotating table
3.
The coding block
32 system is in effect a binary code and provides that
the CCD camera device can accurately and clearly read the code and determine the
position of the container relative to the tooling
10 datum by viewing a
small proportion of the code only (for example two adjacent blocks
32 can
have a large number of unique coded configurations). The coding blocks
32
are made up of vertical data point strings (perpendicular to the direction of extent
of the coding band
31) in each of which there are dark and light data point
zones (squares). Each vertical block
32 contains six data point zones. This
arrangement has benefits over a conventional bar code arrangement, particularly
in an industrial environment where there may be variation in light intensity, mechanical
vibrations and like.
As can be seen in FIG. 4, because the tooling
10 in the exemplary embodiment
is arranged to emboss the same pattern at 180 degree spacing, the coding band
31
includes a coding block pattern that repeats over 180 degree spans.
The position determination system and control of rotation of the tooling
10
are represented in blocks
102 to
105 of the flow diagram of FIG. 1.
The coding band
31 can be conveniently printed contemporaneously with
the printing of the design on the exterior of the container. Forming of the neck
to produce, for example a valve seat
39 (FIG. 3) obscures the coding band
from view in the finished product.
As an alternative to the optical, panoramic visual sensing of the coding band
31, a less preferred technique could be to use an alternative visual mark,
or a physical mark (e.g. a deformation in the container wall) to be physically sensed.
Referring to FIG. 17, the technique is particularly switched to forming
aesthetically pleasing embossed formations
50 of a greater height/depth
dimension(d) (typically in the range 0.3 mm to 1.2 mm) than has been possible with
prior art techniques. Additionally, this is possible with containers of greater
wall thickness(t) than have been successfully embossed in the past. Prior art techniques
have been successful in embossing aluminium material containers of wall thickness
0.075 mm to 0.15 mm. The present technique is capable of embossing aluminium containers
of wall thickness above 0.15 mm, for example even in the range 0.25 mm to 0.8 mm.
The technique is therefore capable of producing embossed containers for pressurised
aerosol dispensed consumer products which has not been possible with prior art
techniques. Embossed monobloc seamless aluminium material containers are particularly
preferred for such pressurised aerosol dispensed products (typically having a delicate
internal anti-corrosive coating or layer protecting the container material from
the consumer product). The present invention enables such containers to be embossed
(particularly registered embossed).
As an alternative to the technique described above in which the embossing tooling
is rotated to conform to the datum situation, immediately prior to the container
being placed in the chuck
4 and secured, the position of the container may
be optically viewed to determine its orientation relative to the datum situation.
If the orientation of the container
1 differs from the desired datum pre-set
situation programmed into the system, then the container is rotated automatically
about its longitudinal axis to bring the container
1 into the pre-set datum
position. With the container in the required datum position, the container is inserted
automatically into the clamp
4 of the holding station, and clamped securely.
In this way the relative circumferential position of the printed design on the
container wall, and the position of the tooling is co-ordinated. There is, thereafter,
no requirement to adjust the relative position of the container and tooling. This
technique is however less preferred than the technique primarily described herein
in which the embossing tooling
10 is re-orientated.
The invention has primarily been described with respect to embossing aluminium
containers of relatively thin wall thicknesses (typically substantially in the
range 0.25 mm to 0.8 mm. It will however be readily apparent to those skilled in
the art that the essence of the invention will be applicable to embossing thin
walled containers/bodies of other material such as steel, steel tinplate, lacquered
plasticised metallic container materials an other non-ferrous or non-metallic materials.
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