Abstract:
A thin walled body is deformed in a process in which the body is gripped securely in a holding station and, whilst gripped in the holding station, tooling engages to deform the peripheral wall of the body at a predetermined wall zone. The tooling is provided at a tooling station which is adjacent the holding station during deformation. The predetermined wall zone is co-aligned with the tooling by rotation of the body about an axis prior to securing at the holding station.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a continuation of U.S. application Ser. No. 11/314,630, which is a continuation of U.S. application Ser. No. 10/182,643, filed Sep. 30, 2002, now U.S. Pat. No. 7,004,000. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     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.  
         [0004]     The invention is particularly suited to embossing of thin walled metallic bodies (particularly aluminum 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.  
         [0005]     2. State of the Art It is known to be desirable to deform by embossing or the like the external cylindrical walls of metallic containers such as aluminum 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.  
         [0006]     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.  
       SUMMARY OF THE INVENTION  
       [0007]     An improved technique has now been devised.  
         [0008]     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 coordinated movement of the tooling prior to deforming engagement with the wall of the body.    
       
 
         [0012]     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 coordinated 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. 
   
 
         [0017]     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.  
         [0018]     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 aluminum 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.  
         [0019]     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.  
         [0020]     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.  
         [0021]     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.  
         [0022]     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.  
         [0023]     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. 
       
 
         [0027]     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.  
         [0028]     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.  
         [0029]     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.  
         [0030]     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.  
         [0031]     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.        
 
         [0034]     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).  
         [0035]     The technique has also made it possible to emboss containers (such as seamless monobloc aluminum containers) provided with protective/anti-corrosive internal coatings or layers without damage to the internal coating or layer.  
         [0036]     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.  
         [0037]     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.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]     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:  
         [0039]      FIG. 1  is a flow diagram of a process according to the invention;  
         [0040]      FIG. 2  is a view of a container to be operated upon in accordance with the invention;  
         [0041]      FIG. 3  is a side view of the container of  FIG. 2  in a finish formed state;  
         [0042]      FIG. 4  is a 360 degree view of a positional code in accordance with the invention;  
         [0043]      FIG. 5  is a schematic side view of apparatus in accordance with the invention;  
         [0044]      FIGS. 6 and 7  are half plan views of apparatus components of  FIG. 5 ;  
         [0045]      FIGS. 8, 9  and  10  correspond to the views of  FIGS. 5, 6  and  7  with components in a different operational orientation;  
         [0046]      FIG. 11  is a schematic close up sectional view of the apparatus of the preceding figures in a first stage of the forming process;  
         [0047]      FIG. 11   a  is a detail view of the forming tools and the container wall in the stage of operation of  FIG. 11 ;  
         [0048]      FIGS. 12, 12   a  to  16 , 16   a  correspond to the views of  FIGS. 11 and 11   a ; and  
         [0049]      FIG. 17  is a schematic sectional view of an embossed zone of a container wall in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]     Referring to the drawings the apparatus and technique is directed to plastically deforming (embossing or debossing) the circumferential wall of an aluminum 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.  
         [0051]     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.  
         [0052]     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 .  
         [0053]     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.  
         [0054]     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.  
         [0055]     In accordance with the invention, in addition to the necking/shoulder-forming tooling at stations  7 , the tooling table carries embossing toiling  10  at an embossing station  9 . The embossing tooling (shown most clearly in FIGS.  11  to  16 ) comprises inner forming tool parts  11   a ,  11   b  of respective arms  11  of an expandible internal tool mandrel  15 . Tool parts  11   a ,  11   b  carry respective female embossing formations  12 .  
         [0056]     The embossing tooling  10  also includes a respective outer tool arrangement including respective arms  13  carrying tooling parts  13   a ,  13   b  having complementary male embossing formations  14 . In moving to the table  7  advanced position the respective internal tool parts  11   a ,  11   b  are positioned internally of the container spaced adjacently the container  1  wall; the respective external tool parts  13   a , 13   b  are positioned externally of the container spaced adjacently the container  1  wall.  
         [0057]     The internal mandrel  15  is expandible to move the tooling parts  11   a ,  11   b  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  11   a ,  11   b  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  11   a , 11   b . 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  11   a ,  11   b  to cause expansion (moving apart) of the tool parts  11   a ,  11   b . The resilience of arms  11  biases the mandrel  15  to the closed position as the rod  16  moves in the direction of arrow B.  
         [0058]     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  13   c  of respective arms  13 . Movement of actuator  21  in the direction of arrow D causes the external tooling parts  13   a  to be drawn toward one another. Movement of actuator  21  in the direction of arrow E causes the external tool parts  13   a  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.  
         [0059]     As an alternative to the cam/wedge actuation arrangement, other actuators may be used such as hydraulic/pneumatic, electromagnetic (e.g. solenoid actuators) electrical (servo/stepping) motors.  
         [0060]     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  13   a.    
         [0061]     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.  
         [0062]     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  11   a  to lie against the internal circumferential wall of cylinder  1 , adopting the configuration shown in  FIGS. 12, 12   a . Next actuator  21  moves in the direction of arrow D causing cam arms  20  to act on cam shoulder  13   c  and flexing arms  13  toward one another. In so doing the external tooling parts  13   a  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  11   a.    
         [0063]     The deforming tooling parts  11   a ,  13   a , 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.  
         [0064]     An important feature is that the internal tooling parts  11   a  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, 13   a . The configuration and arrangement of the cam arms  20 , cam shoulders  13   c  of the external embossing tooling and the sloping (or wedge) cam surface of internal tooling parts  11   a  (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  13   a  is rearward of the embossing formations  14 ; the internal cam force action on the inner tool parts  11   a  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 .  
         [0065]     Next actuator  21  returns to its start position (arrow E) permitting the arms  13  of the external toiling to flex outwardly to their normal position. In so doing tooling parts  13   a  disengage from embossing engagement with the container  1  external surface. At this stage in the procedure, the situation is as shown in  FIGS. 14, 14   a.    
         [0066]     The next stage in the procedure is for the internal mandrel to collapse moving tooling parts  11   a  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, 15   a .  
         [0067]     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, 16   a.    
         [0068]     In the embodiment described, the movement of the tools to effect embossing is translational only. It is however feasible to utilize rotational external/internal embossing tooling as is known generally in the prior art.  
         [0069]     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 .  
         [0070]     The embossing stages described correspond to stages  106  to  112  in the flow diagram of  FIG. 1 .  
         [0071]     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.  
         [0072]     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.  
         [0073]     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.  
         [0074]     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 .  
         [0075]     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.  
         [0076]     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.  
         [0077]     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 .  
         [0078]     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.  
         [0079]     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.  
         [0080]     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 aluminum material containers of wall thickness 0.075 mm to 0.15 mm. The present technique is capable of embossing aluminum 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 aluminum 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).  
         [0081]     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 coordinated. 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.  
         [0082]     The invention has primarily been described with respect to embossing aluminum 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.