Abstract:
The invention concerns an apparatus ( 10 ) for simultaneously blowing and filling a plastic container from a preform, the apparatus comprising: a mold ( 14 ) for enclosing a preform, so as to leave access to the mouth of the preform, stretching means ( 42 ) for stretching the preform within the mold, an injection head ( 16 ) for injecting a liquid through the mouth so as to cause expansion of the preform within the mold, thereby obtaining a blown and filled container ( 12 ) that comprises a dispensing opening ( 22 ), characterized in that the apparatus further comprises a capping head ( 18 ) for fixing a cap ( 40 ) on the dispensing opening of said blown and filled container, the capping head being permanently arranged between the injection head ( 16 ) and the mold ( 14 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a National Stage of International Application No. PCT/EP2012/065116, filed on Aug. 2, 2012, which claims priority to European Patent Application No. 11176852.9, filed Aug. 8, 2011, the entire contents of which are being incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to an apparatus for blowing and filling plastic containers from preforms. 
     BACKGROUND 
     Plastic containers such as bottles of water are manufactured and filled according to different methods including blow moulding or stretch-blow moulding. 
     According to one of these known methods a plastic preform is first manufactured through an injection molding process and then heated before being positioned inside a mould. 
     The preform usually takes the form of a cylindrical tube of sod at its bottom end and open at its opposite end. 
     Once the preform has been positioned within the mould only the open end of the preform is visible from above the mould. 
     This method makes use of a stretch rod which is downwardly engaged into the open end of the preform so as to abut against the closed bottom end thereof. The stretch rod is further actuated to be urged against the closed end, thereby resulting in stretching the preform. 
     After the stretching phase has been initiated a liquid is also injected into the preform through its open end. This liquid injection causes expansion of the preform until coming into contact with the inner was of the mould, thereby achieving the final shape of the bottle. 
     The bottle which has been thus manufactured and filled within the mould has then to be sealed with a cap. 
     In this respect, the mould is opened and the bottle filled with liquid is transferred to a station provided with a capping head. 
     A cap is placed within the capping head and the latter is rotated around the threaded neck of the bottle so as to screw the cap around the neck. 
     Although this method proves to be satisfactory, there is nevertheless a need to make the blowing, filling and capping process easier. 
     SUMMARY OF THE INVENTION 
     In this respect, the invention provides an apparatus as defined in claim  1 . 
     In the apparatus according to the invention the capping head is located between the injection head and the mould during the blowing and filling of the container (through stretching and expansion operations). Thus, once the container has been blown and filled there is no need to raise the injection head and bring a capping head between the latter and the mould which still encloses the container since the capping head is already in place, at the appropriate location. 
     There is no need either to transfer the filled and opened container towards a distant station equipped with a capping head, thereby avoiding, or at least reducing, splashing of the liquid when being moved. 
     Thus, the blowing, filling and capping process gets simplified and faster than in the prior art. 
     According to one feature, the capping head has a traversing hole that is centered about an axis of alignment along which the injection head and the mould are aligned, said traversing hole enabling injection of the liquid into the opening of the container from the injection head. 
     Thus, the traversing hole of the capping head is arranged between the injection head and the mould and, more particularly, is facing both the cutlet of the injection head through which liquid exits and the dispensing opening of the container. 
     It is to be noted that the axis of alignment also passes by the dispensing opening of the container, in the middle thereof. 
     According to one possible feature, the capping head is mounted on the injection head. 
     This provides a simple arrangement of the capping head between the injection head and the mould. 
     More particularly, the capping head is mounted under the injection head. 
     According to a more specific feature, the capping head is rotatably mounted relative to the injection head. 
     This mounting is particularly convenient for a subsequent step during which a cap will be screwed around the neck of the dispensing opening. 
     However, other kind of capping operations may be envisaged which do not require a rotating capping head. 
     Thus, other capping techniques may be envisaged such as screw capping, press on capping, sealing capping (with aluminum foil), and ultrasonic sealing capping. 
     According to another possible feature, the apparatus comprises driving means for driving the capping head in rotation around an axis of rotation that coincides with the axis of alignment of the injection head and the mould. 
     Thus, the apparatus comprises appropriate means for driving a capping head in rotation with a view to fixing a cap on the dispensing opening of the container. 
     Such driving means can be permanently integrated in the apparatus, which, therefore, does not necessitate bringing them close to the capping head when needed. 
     More particularly, said driving means may be laterally offset relative to the axis of rotation. 
     This arrangement makes it possible to accommodate said driving means in the apparatus in a permanent manner (the driving means are located in a position which does not hinder the longitudinal movement of the injection head), while the capping head is permanently disposed between the injection head and the mould. 
     Thus, the laterally offset driving means enable driving in rotation of the capping head for capping purpose without changing the position of the capping head and the driving means after the container has been blown and filled. 
     According to one possible feature, said driving means are coupled to the periphery of the capping head, e.g. through a mesh engagement. 
     According to another possible feature, said driving means are activated while the container is maintained within the mould in a fixed position. 
     This feature is advantageous in that the mould enclosing the blown and filled container remains at the same location as that occupied during the blowing and filling process and still keeps the container in place. 
     Splashing of the liquid in the container is therefore avoided. 
     According to another possible feature, said driving means comprise a brushless motor. 
     These kinds of driving means enable accurate control of the screwing torque during the screwing operation of a cap around the threaded neck of the dispensing opening. 
     Alternatively, another kind of motor may be envisaged together with a magnet coupling. 
     It is to be noted that the mould maintaining the container in position during the capping operation is used as an anti-rotating means. 
     According to another possible feature, the capping head has receiving means for receiving a cap to be fixed on the opening of the container and holding means for holding said cap within said receiving means. 
     According to another possible feature, said receiving means comprise the traversing hole. 
     Thus, the cap is received within the traversing hole and may be tightly fitted therein thanks to appropriate sizing of the internal dimensions of the traversing hole and external dimensions of the cap. 
     According to a possible feature, said holding means are arranged around the traversing hole. 
     Such holding means may be, e.g. the internal walls of the traversing hole and/or elastic means provided therein. 
     According to another possible feature, said stretching means comprise a stretch rod. 
     In a conventional manner, such stretching means are used during the fling phase for stretching the preform within the mould. 
     According to another possible feature, the apparatus comprises actuation means for causing the stretch rod to move downwardly towards the receiving means in which a cap may be blocked. 
     The stretch rod has a dual purpose since it both participates in stretching the preform within the mould during the blowing and filling process and releasing a cap which has been blocked within the receiving means of the capping head. 
     According to another possible feature, the injection head is mobile in a translational movement. This movement is performed along the longitudinal axis of alignment of the injection head and the mould. 
     According to another possible feature, the injection head and the capping head are mobile together in a translational movement so as to bring the capping head against the mould or move it away therefrom. 
     Such a translational movement makes it possible for the capping head to come into contact with the mould around the dispensing opening of the container. For instance, this may occur during the blowing and filling process. Such a movement makes it possible for the capping head to move away from the mould, e.g. when a cap has to be provided to the capping head. 
     According to another possible feature, the apparatus comprises:
         bringing means for bringing a cap to be fixed on the opening of the container between the capping head and the mould after the capping head has been moved away from the mould, and   positioning means for positioning said cap within the receiving means of the capping head.       

     Thus, when the capping head has been moved away from the mould, an appropriate space has been left between the capping head and the dispensing opening of the container which protrudes from the mould. This space is used for disposing therein said movable bringing and positioning means. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures in which: 
         FIG. 1  is a schematic and overall view of an apparatus according to the invention with its main components; 
         FIG. 2  is a schematic and partial view of the apparatus of  FIG. 1  with means for bringing and positioning a cap on the capping head; 
         FIGS. 3A-D  are successive schematic views illustrating the different operations for bringing and positioning a cap on the capping head and fixing it on the dispensing opening of the container: 
         FIGS. 4A and 4B  are two successive views showing the use of a stretch rod to disengage a cap trapped inside the capping head. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates a schematic and partial view of the main components of an apparatus  10  for simultaneously blowing and filling a plastic container from a preform. 
     As represented in  FIG. 1 , the container is a bottle  12  which has been filled with a liquid. 
     Apparatus  10  comprises a mould  14  enclosing bottle  12  in the position of  FIG. 1 . 
     Also, apparatus  10  comprises an injection head  16  through which the liquid has been injected into the bottle during its shaping. 
     Apparatus  10  also comprises stretching means which, here, comprise a stretch rod represented in  FIGS. 4A and 4B  and which will be described subsequently. 
     Apparatus  10  further comprises a capping head  18  that is rotatably mounted relative to injection head  16 . 
     As represented in dotted lines, capping head  18  has a traversing hole  20  that is centered about a longitudinal axis A. 
     Axis A is an axis of alignment along which injection head  16  and mould  14  are aligned in the manufacturing configuration of  FIG. 1 . 
     Traversing hole  20  has two opposite sides  20   a  and  20   b . Side  20   a  faces injection head  16  while opposite side  20   b  faces mould  14  and, more particularly, the dispensing opening  22  of container  12 . 
     Although not represented in the drawings, injection head  16  has an outlet through which liquid flows before entering into traversing hole  20  and dispensing opening  22  when capping head  18  rests against mould  14  and traversing hole  20  surrounds dispensing opening  22 . 
     This position is not illustrated in the drawings and represents the position in which the container is simultaneously blown and filled. 
     Furthermore, apparatus  10  comprises driving means  24  for driving capping head  18  in rotation around an axis of rotation that coincides with longitudinal axis of alignment. 
     As represented in  FIG. 1 , driving means  24  are laterally offset relative to axis A and are coupled to the periphery of capping head  18 . 
     More particularly, driving means comprise a gear  26  which cooperates with a gear  28  provided at the periphery of capping head  18 . 
     These gears may be in a mesh engagement and for instance, may be toothed gears. 
     Gear  26  is for instance mounted on the output shaft  30  of a motor  24 . 
     Motor  24  is for example a brushless motor. 
     This motor makes it possible to accurately control the force transmitted to capping head  18  and therefore to the cap during the screwing process that will be described subsequently. 
       FIG. 1  shows a manufactured container  12  after it has been simultaneously blown and filled with a liquid through a conventional process such as described in the Applicant&#39;s patent application EP 1 529 620. 
     Briefly, container  12  has been produced from a plastic preform. 
     According to this known process, the plastic preform is first manufactured through a moulding process and then heated before being positioned within mould  12  so as to leave access to the mouth of the preform. 
     Thus, the mouth of the preform protrudes from the upper part of the mould which encloses the rest of the preform. 
     Mould  14  may be spited into two or more parts depending on the manufacturing process. 
     The preform usually assumes the shape of a cylindrical tube closed at its bottom end and open at its opposite end. 
     Once the preform has been positioned within the mould, only the open end of preform with its protruded mouth is visible from above the mould. 
     The open end is shaped during the process, thereby leading to dispensing opening  22 . 
     The blowing and filling process makes use of a stretch rod (represented in  FIGS. 4A and 4B ) which is downwardly engaged into the open end of the preform so as to come into contact with the closed bottom end thereof. 
     The stretch rod is then further actuated to push the closed end downwardly and stretch the preform accordingly in a controlled manner. 
     After the stretching phase has been initiated, the liquid supplied by the injection head  16  is injected into the preform through its open end around the stretch rod, while the latter is still being actuated. 
     This liquid injection causes expansion of the preform together with the movement of the stretch rod until coming into contact with the inner walls of the mould. 
     The final shape of the container  22  is thus achieved. 
     Once the container has been blown and filled according to the above-described process, a cap has to be fixed to the dispensing opening  22  of the container. 
     In this respect, injection head  16  and capping head  18  which are mobile together in a translational movement along axis A are caused to be raised along axis A so as to leave free sufficient space between capping head  18  and dispensing opening  22 . 
     It is to be noted that the connection between injection head  16  and capping head  18  is a rotatable connection comprising needle bearings. 
     Such a rotatable connection is known to the skilled person. 
     It is to be noted that dispensing opening  22  has a neck  32  with an outside thread  34  and a flange  36  that is provided at the basis of the neck. Flange  36  is positioned within a recess provided in the upper part of mould  14 . 
       FIG. 2  is a schematic and simplified view representing container  12  maintained within mould  14  and capping head  18  away from mould  14  and neck  32 . 
     Apparatus  10  comprises bringing means  38  for bringing a cap  40  to be fixed on dispensing opening  22 . Bringing means  38  have been moved from a rest position (not represented) to an active position located between capping head  18  and dispensing opening  22 . 
     Bringing means  38  may assume the shape of a cap distributing plate provided, for instance, with a slight recess on the upper surface thereof for positioning and maintaining in a fixed position cap  40  on the plate. 
     This plate may be a rotating plate comprising several caps at its periphery or an elongated plate which carries only one cap at one end and is elongated along an axis that is perpendicular to axis A. 
       FIGS. 3A to 3D  illustrate successive views showing the capping process of the container. 
       FIG. 3A  is identical to  FIG. 2  where cap  40  has been brought between capping head  18  and neck  32  and positioned below traversing hole  20  vis-à-vis side  20   b  thereof. Injection head  16  and attached capping head  18  are actuated to be lowered towards bringing means  38  and cap  40 . 
     As represented in  FIG. 3B , capping head  18  is moved downwardly towards neck  32  and cap  40  is forcibly engaged within traversing hole  28  as capping head  18  is actuated downwardly. 
     The inner dimensions of the traversing hole  20  (inner diameter) and the outer dimensions of cap  40  (outside diameter) are adjusted so that cap  40  can be introduced in force within traversing hole  20  and remain in place as represented in  FIG. 3C . 
     It is to be noted that cap  40  is partly engaged within hole  20 . 
     Cap  40  is kept in position within receiving means of capping head (inner whole of traversing hole  20 ) thanks to friction forces. Cap  40  is tight fitted within filled said receiving means. 
     The degree of introduction of cap  40  into traversing hole  20  depends on the respective dimensions of the cap and the hole. The more the respective dimensions correspond to each other, the less cap  40  is introduced into traversing hole  20 . 
     In the present embodiment, cap  40  has been positioned within the receiving means of the capping head  18  only by virtue of the translational movement of the injection head and capping head. 
     This is a very convenient means for putting in place the cap within the capping head which does not require any other device. Moreover, bringing means  38  may be simplified since they do not need to be movable along vertical axis A. 
     However, other positioning means may be envisaged for positioning the cap within the receiving means of capping head  18 . 
     Other bringing means for bringing cap  40  between capping head  18  and the dispensing opening of the container may be alternatively envisaged. 
     Reverting to  FIG. 3C , once cap  40  has been appropriately positioned within traversing hole  20  bringing means  38  are withdrawn as indicated by the arrow. 
     Next, capping head  18  equipped with cap  40  is driven into a downwardly translational movement along axis A thanks to the accordingly actuated injection head  16  so as to place cap  40  around neck  32 . 
     As represented in  FIG. 3D , driving means  24  are activated in order to drive into rotation capping head  18  such as already described above. 
     Capping head is therefore driven into rotation around axis A. This rotational movement of capping head  18  causes cap  40  to be driven into rotation around neck  32 , thereby tightly screwing cap  40  around the neck of the container. 
     Other capping techniques may be alternatively envisaged for capping container  12 . For instance, press-on cap type or ultrasonic sealing techniques may be used. In case of ultrasonic sealing, the neck and the cap may be made together using over-moulding techniques. 
     It will be appreciated that the apparatus which has been described is of a particularly simple construction and has movable parts or components which are capable of moving only according to fewer and simple movements (translation and rotation). 
     Also, the capping head is either driven into a translational movement along longitudinal axis A (for example vertical axis) during the blowing, filling and capping process or driven into rotation during the last step of the capping process ( FIG. 3D ). 
       FIGS. 4A and 4B  represent injection head  16  and capping head  18  only. Mould  14  and closing container  12  are still located under the capping head but have been removed for clarity purpose. 
     As represented in  FIG. 4A , apparatus  10  comprises a stretch rod  42  which is in a sliding connection within injection head  16 . 
     Stretch rod  42  is actuated by conventional actuating means not represented in the drawings and which cause it to move upward and downward along longitudinal axis A. 
     Injection head  16  comprises an inner housing  44  which is substantially cylindrical in shape and accommodates therein stretch rod  42  as well as an injection nozzle not represented in the drawings for the sake of clarity. 
     The injection nozzle rests against the frusto-conical inner surface  46  of the inner housing  44  to achieve fluidtight sealing when injection of fluid into the container is no longer necessary. 
     This injection nozzle stays in this resting position during the capping process which has been described above. 
     The injection nozzle is perforated in its middle portion so as to receive stretch rod  42  therein. 
     In  FIG. 4A , a cap  48  is held within the receiving means (traversing hole  20  of injection head  18 ). 
     However, cap  48  is incorrectly positioned within injection head  18 . 
     For instance, cap  48  has been introduced within traversing hole  20  over a too great distance which has led to blocking the cap. 
     Alternatively, the cap may have been introduced within hole  20  in a slanted manner, thereby leading to blocking it inside the hole. 
     This blocking situation may be detected when positioning a cap within the injection head ( FIG. 3B ) or when fixing the cap on the dispensing opening of the container ( FIG. 3D ), for instance after screwing it and trying to move the injection head away from the  FIG. 3D  position. 
     This situation has been addressed as illustrated in  FIGS. 4A and 4B  using stretch rod  42 . 
     As represented in  FIG. 4B , when cap  48  has been detected as being blocked stretch rod  42  is caused to move downwardly towards injection head  18  and more particularly, receiving means  20 . 
     Stretch rod  42  then exerts a vertical force on cap  48  and pushes it downwardly out of receiving means  20  as illustrated in  FIG. 4B , thereby freeing said receiving means and removing the blocked cap.