Method for angular orientation of hollow bodies in container manufacturing equipment

Abstract

The present invention relates to a method for adjusting the angular position of a hollow body (12) in a container (12B) manufacturing device (10), wherein the hollow body (12) is moved by separate supporting members (38, 88), each of which is equipped with a device for rotating the hollow body (12) around its axis (Z1), and the method comprises a first measuring step (E1), the first measuring step being used to measure the angular deviation (α) of at least one determined hollow body (12) relative to a reference angular position in a measuring area (107B, 107C, 107D), and is characterized in that it also comprises a second compensation step (E2), the second compensation step compensating the angular position of a subsequent hollow body (12) in a compensation area (112A, 112B, 112C) arranged upstream of the measuring area (107B, 107C, 107D) according to the angular deviation (α) measured for the at least one determined hollow body (12).

Description

Technical Field

[0001] The invention relates to a method for adjusting the angular position of a hollow body in a manufacturing device for manufacturing containers by molding preforms made of thermoplastic material. In the manufacturing device, the hollow bodies are moved in a row along a production path by means of separate supporting members, each supporting member being equipped with a device for rotating the hollow body around a hollow body axis. The method comprises a first measuring step for measuring the angular deviation of at least one determined hollow body relative to a reference angular position in a determined measuring area of ​​the production path. Background Art

[0002] In the following description and claims, the term "hollow body" refers indiscriminately to a preform or a container.

[0003] It is known to produce thermoplastic material, in particular polyethylene terephthalate (PET) containers by shaping, in particular stretch-blowing, a preform whose body has been previously heated. The hollow body has a neck which has been molded into its final shape and which is thus intended to remain unchanged during the container manufacturing process.

[0004] In many cases, preforms are made by injection molding at a first location and blow molded into the final container shape at a second location on specialized manufacturing equipment. This technology allows the blow molding process to be carried out as close as possible to the bottling location, while the injection molding process can be carried out at any location. In fact, it is relatively easy and inexpensive to transport preforms of relatively small dimensions, while transporting molded containers has the disadvantage of being economically unprofitable due to their very large volume.

[0005] Such large-scale production of containers is carried out in container manufacturing plants in which the hollow bodies travel successively along a production path.

[0006] To allow the preform body to be shaped, it is heated above the glass transition temperature, thereby making the walls of the body ductile. Conversely, the neck is kept at a temperature below the glass transition temperature in order to avoid deformation of the neck. To this end, the manufacturing plant comprises a heating station that allows the preform body to be heated to the temperature required to carry out the shaping step.

[0007] Afterwards, the preforms thus heated are then sent to a forming station of a manufacturing plant. The forming station is equipped with a plurality of forming stations, each of which comprises a mould and an injection device for injecting a pressurized forming fluid into the preform received in the mould. A large number of forming stations allows the production of containers at a high rate, for example greater than or equal to 50,000 bottles per hour. The forming stations are carried, for example, by a turntable, which rotates so that the preforms are blown one after another at a high rate while moving between a point of introduction corresponding to the introduction of the preform into the associated mould and a point of demoulding corresponding to the discharge of the moulded container outside the mould.

[0008] The containers thus obtained are received at their die outlet by the grippers of a transfer wheel so that they are transported in a row to another device, for example by a conveyor belt. The next station is, for example, a filling station or a labeling station.

[0009] These stations are generally equipped with container conveying devices, such as turntables. Therefore, the manufacturing equipment is also equipped with a device for conveying between two stations.

[0010] Sometimes it is necessary to change the angular orientation of a hollow body during its movement through a manufacturing apparatus.

[0011] This change in angular orientation is necessary, for example, when the container to be obtained has at least one section that is not axisymmetric relative to the neck axis. To obtain such a non-axisymmetric container, the preform is usually heated preferentially in some sections, in a process generally known as "preferential heating". The preform is then received in the mold in a fairly defined orientation about its main axis, so that the heating profile of the body matches the mold cavity of the non-axisymmetric container to be obtained.

[0012] In order to ensure controlled orientation of the preforms between their introduction into the heating station and their exit from the forming station, the conveying device has a separate supporting member for holding the preforms in order to avoid slipping between the preforms and their separate supporting member, and in particular to avoid any uncontrolled rotation of the preforms about their main axis.

[0013] It is known to provide the neck of a preform with angular markings which allow the angular orientation of the preform relative to the support about the neck axis to be controlled and corrected. Since the neck retains its shape during the production of the container, the angular markings can still be used to allow the orientation of the preform and the finished container about its neck axis throughout the manufacturing process and during subsequent processing.

[0014] The angular marking allows determining the angular orientation of the preform or container relative to each individual support member and possibly changing the angular orientation of the preform or the individual support members to bring the angular marking to a reference position determined relative to the individual support members.

[0015] Without limitation, such angular markings can be realized during the injection molding of the preform in the form of undulating angular markings. For example, they are cutouts made in the neck collar, or even lugs made in a groove located above the collar. Thus, the preform is already provided with its angular markings before being fed into the container manufacturing machine.

[0016] When the heating station is loaded with a preform, a first angular indexing of this preform is performed so that the heating profile coincides with the angular markings already provided on the preform.

[0017] However, when the preform is transferred from one conveyor to the next, it may occur that the preform undergoes an uncontrolled pivoting about its main axis relative to the individual support members. Likewise, when the preform is placed in the mold of the molding station, the preform remains free to rotate about its main axis during the very short period of time between the moment it is released in the mold by the directly upstream conveyor and the moment it is locked by the nozzle of the molding station.

[0018] To solve this problem, for each preform, when an angular deviation is detected relative to a reference angular position, the orientation of the preform is checked in a measuring area of ​​its production path, and when a correction process is performed in a correction area of ​​the production path arranged downstream of the measuring area, for example when the preform is loaded by a forming station, the orientation of the preform is corrected so that the heating profile of the preform generally corresponds to the mold cavity of the mold.

[0019] According to a known variant, the correction is carried out without measurement by rotating the preform until a sensor detects that an angular mark provided on the neck is in a reference angular position.

[0020] However, when a preform is loaded into the heating station with an angular indexing error, its heating profile no longer coincides with its angular markings. This error is reflected in the mold, since the orientation of the preform in the mold is determined with the help of its angular markings. It is therefore necessary to check the orientation of the preform at the beginning of the heating stroke in a measuring area and then correct the orientation of the preform downstream of the measuring area so that its heating profile generally corresponds to the position of the angular markings.

[0021] However, the duration of each correction step of the preform position is proportional to the value of the angular deviation to be corrected in the correction zone. As a result, the production throughput is limited by the correction steps.

[0022] In addition, the heating profile is sometimes slightly offset relative to the position of the angular marks. This may be caused by preform slippage between the first measurement area and the heating station loading the preform. Summary of the invention

[0023] The present invention proposes a method for adjusting the angular position of a hollow body in a manufacturing device, the manufacturing device being used to manufacture containers by molding preforms made of thermoplastic material, in which the hollow bodies are moved in a row along a production path by means of separate supporting members, each supporting member being equipped with a device for rotating the hollow bodies around the axis of the hollow body, the method having a first measuring step for measuring the angular deviation of at least one determined hollow body relative to a reference angular position in a determined measuring area of ​​the production path, characterised in that the method has a second compensation step for compensating the angular position of a subsequent hollow body in a compensation area arranged upstream of the measuring area, during which the angular orientation of the subsequent hollow body is modified with an updated compensation angle so as to reduce the angular deviation of the subsequent hollow body in the measuring area, the updated compensation angle depending on the angular deviation measured for the at least one determined hollow body during the first measuring step and on the current compensation angle.

[0024] According to other features of the present invention:

[0025] - modifying the value of the current compensation angle in the second compensation step when the average value of the angular deviation of each hollow body in a series of at least two consecutively determined hollow bodies measured in the first determination step is greater in absolute value than a determined threshold value;

[0026] - during a second compensation step, calculating an updated compensation angle by subtracting the mean value of the angular deviations of the series of preforms determined from the current compensation angle;

[0027] - the method is iterated in a loop, and the current compensation angle is formed by the updated compensation angle of the previous iteration;

[0028] -In the first iteration, the current compensation angle is initialized to 0°;

[0029] - the manufacturing device comprises a heating station provided with a conveying device equipped with supporting members called swivels, each of which is capable of conveying a preform individually along a heating path forming a section of the production path, each of which is capable of rotating the preform about the preform axis, the compensation zone being arranged on the heating path, the compensation of the angular position of the preform being carried out by rotating each swivel by said updated compensation angle when the preform passes through the compensation zone;

[0030] The conveying device has a chain in the form of a swivel, the movement of which is guided by two guide wheels, the compensation area being located on the chain section which meshes with one of the guide wheels;

[0031] the compensation zone is located on the chain section meshing with the guide wheel downstream of the loading point where the preforms are transferred from the upstream conveyor before the heating of the preforms begins;

[0032] the measuring area is located in the heating station on the chain section meshing with the guide wheel upstream of the transfer point for transferring the preforms after the heating of the preforms has ended in the direction of the forming station to a downstream conveyor;

[0033] the manufacturing plant has a forming station in which each hollow body moves along a forming stroke forming a section of a production path and along which each preform undergoes a forming step to form a final container;

[0034] the compensation zone is located on the chain section meshing with the guide wheel upstream of the transfer point of the preforms after the end of the heating of the preforms in the direction of the forming station to the downstream conveyor;

[0035] - the measuring area is located in a forming station arranged downstream of the heating station before the start of the forming process;

[0036] - The compensation area is positioned along the forming stroke before the forming process begins;

[0037] The measuring area is located in the forming station along the forming path after the forming process has been completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features and advantages of the present invention will become apparent from the following detailed description when read with reference to the accompanying drawings, in which:

[0039] Figure 1 is a top view schematically showing a manufacturing apparatus for manufacturing a container using a preform;

[0040] Figure 2 is intended to be Figure 1 A profile of a preform loaded into a manufacturing device;

[0041] Figure 3 is a schematic representation of Figure 1 An enlarged top view of a heating station of the manufacturing equipment shown;

[0042] Figure 4 is along Figure 3 A cross-sectional view of section 4-4 showing a portion of a preform transport chain passing through a heating station;

[0043] Figure 5 is along Figure 3 A cross-sectional view of section 5-5 of FIG. 5 showing a preform carried by a swivel engaged with a swivel orienting device;

[0044] Figure 6 is along Figure 5 A cross-sectional view of section 6-6 showing the crank pin of the swivel seat engaged between two fingers of the orienting device;

[0045] Figure 7is an axial cross-section showing Figure 1 The forming station of the apparatus shown is equipped with a forming table, in which a preform is placed, and the nozzle of the forming table is in the extreme retracted position;

[0046] Figure 8 Similar to Figure 7 , showing that the nozzle is in an extreme working position suitable for injecting a molding fluid into the interior of the preform;

[0047] Fig. 9 Similar to Figure 7 , wherein the nozzle is in an intermediate orientation position and a drive member of the nozzle is engaged with the preform to drive the preform to rotate;

[0048] Fig.10 is a front view showing a turntable of a molding station, the turntable carrying a plurality of molding tables, and the molding station is equipped with two camera devices;

[0049] Fig.11 is a perspective view showing the hollow body neck with four angular markings;

[0050] Fig.12 is a top view showing the neck of the preform as it passes through an aiming point aimed at by one of the camera devices of the apparatus, the preform being oriented at a present first angular orientation;

[0051] Fig.13 Similar to Fig.12 , showing another preform oriented at a present second angular orientation;

[0052] Fig.14 Shown by Fig.12 The camera device captures the Fig.12 An image of the neck of the preform;

[0053] Fig.15 Shown by Fig.13 The camera device captures the Fig.13 An image of the neck of the preform;

[0054] Fig.16 A graph is shown, wherein the measured angular deviation between the current angular position of the hollow body and the reference angular position is represented on the abscissa, the number of hollow bodies having the angular deviation is represented on the ordinate, and the curve represents the distribution of the angular deviation for a series of multiple hollow bodies, the average value of the angular deviation being offset relative to the 0° value;

[0055] Fig.17 Shows something like Fig.16 , where the average angular deviation is equal to 0°;

[0056] Fig.18 is a block diagram illustrating a compensation method implemented in accordance with the teachings of the present invention. DETAILED DESCRIPTION

[0057] Hereinafter, the same reference numerals will be used to indicate elements having the same structure or similar function.

[0058] Figure 1 1 shows a manufacturing apparatus 10 for manufacturing a container 12B using a preform 12A. In the following and in the claims, the general term "hollow body 12" will be used to refer to both the preform 12A and the container 12B without distinction.

[0059] In the following, the terms “upstream” and “downstream” will be used with reference to the direction of movement of the row of hollow bodies 12 along the production path 13 .

[0060] The present invention is intended to be applied when manufacturing apparatus 10 is producing containers 12B.

[0061] Here, the production path 13 extends in a generally horizontal plane, whereas the hollow body 12 has a main axis Z1 which extends vertically, ie orthogonally, to the horizontal plane.

[0062] The hollow body 12 is along Figure 1 A production path 13 indicated above with a thick line continuously moves through the manufacturing device 10. The movement of the hollow bodies 12 is carried out by various conveying devices, some of which will be described in detail below, which have individual support members for supporting each hollow body 12. The conveying devices are arranged in a chain so that each hollow body 12 can be transferred from one conveying device to another conveying device so that the hollow body is always held by at least one individual support member and continues to move along the production path 13.

[0063] Hereinafter, angle values ​​are expressed in degrees.

[0064] Figure 1 Schematically shown in FIG. 1 is a manufacturing device 10 for batch manufacturing of thermoplastic material containers 12B using preforms 12A. The container 12B is a bottle here without limitation. Here, the thermoplastic material is formed by polyethylene terephthalate, which is indicated by its acronym "PET" hereinafter.

[0065] Figure 2 1 shows an example of a hollow body 12, here in the form of a preform 12A. This preform 12A is made of a thermoplastic material, here polyethylene terephthalate (PET). The preform 12A is generally axially symmetrical and has Figure 2 The preform includes a main axis "Z1" shown vertically in FIG. Figure 2 The main body 14 of the lower part has a closed axial end. The main body 14 is shown in Figure 2The upper part opens at its opposite ends into an open neck 16. Neck 16 has a tubular shape, the main axis of which defines the main axis "Z1" of preform 12A.

[0066] The body 14 has a generally axially symmetrical shape in the form of an elongated tube along a main axis "Z1". The neck 16 of the preform also comprises a radially projecting annular collar 18. The neck 16, including the collar 18, is defined externally by an outer surface 17.

[0067] A portion of the outer surface 17 of the neck 16 has a generally cylindrical shape. The outer surface typically includes closure fixing means, such as threads or grooves for elastic engagement of the closure.

[0068] Reference Figure 1 , the manufacturing device 10 comprises a heating station 20 for heating the preform 12A. As a non-limiting example, the heating station 20 has a heating member 22, such as a halogen lamp or a laser emitter, which emits heating electromagnetic radiation, such as infrared radiation. Generally speaking, a reflector (not shown) is arranged facing each heating member 22 on both sides of the heating path so as to reflect the heating radiation in the direction of the preform.

[0069] As will be explained in more detail below, the heating station 20 has a conveying device 24 for conveying the hollow body 12 in the form of a preform 12A, which is arranged to cause the hollow body 12 to travel along the heating member 22. The travel direction of the preform 12A is determined by Figure 1 The arrows show.

[0070] On leaving the heating station 20, the body 14 of the preform 12A is rendered ductile by heating above the glass transition temperature, while the neck 16 is maintained at a temperature low enough to retain its original shape.

[0071] The manufacturing plant 10 also comprises a forming station 26 for forming the preforms 12A thus heated into finished containers 12B. The forming station 26 is arranged downstream of the heating station 20 with reference to the flow of hollow bodies 12 along the production path 13 .

[0072] The forming station 26 here comprises a turntable 28 carrying a plurality of forming stations 30. The turntable 28 is mounted so as to be able to rotate about a central axis "Z2". Thus, each forming station 30 can be moved about the axis "Z2" of the turntable 28 between an input point 32 for the hot preforms 12A and a demolding point 34 for the finished containers 12B before restarting a new cycle. The forming stations 30 will be described in more detail below.

[0073] Reference Figure 3 , shows the heating station 20 in more detail. The transport device 24 allows the preforms 12A to be moved in a line along a heating path 36, which is Figure 3 The heating path 36 forms a section of the production path 13 .

[0074] The transport device 24 comprises a chain 37 composed of individual supporting members, hereinafter referred to as "swivel seats 38", each of which is suitable for supporting a single preform 12A.

[0075] like Figure 4 As shown, such a swivel 38 comprises a mandrin 40 which is here temporarily secured to the neck 16 of the preform 12A while it is conveyed along the heating path 36. In particular, the preform 12A is secured against rotation relative to the mandrin 40 about its main axis "Z1".

[0076] For example, the cartridge 40 is pressed into the neck 16 of the preform 12A, which is thus temporarily secured by friction to the cartridge 40. The necessary friction is provided, for example, by a ring of elastomeric material (not shown) arranged in a groove around the cartridge 40.

[0077] The chuck 40 is fixed to the lower end of a shaft 42, the axis "Z3" of which is coaxial with the main axis "Z1" of the preform 12A carried. The shaft 42 is housed in a guide bearing 44 of a link 46 of the transport device 24. More specifically, the shaft 42 is rotatably mounted in the guide bearing 44 about its main axis "Z3". This rotation advantageously enables the entire body 14 of the preform 12A to be exposed in a controlled manner to the heating radiation emitted by the heating member 22.

[0078] Furthermore, the shaft 42 is mounted here so as to be able to slide vertically relative to the chain ring 46. The chain ring 46 comprises a lower sleeve 48 having an annular lower end surface referred to as the “unloading surface 50”. Thus, the shaft 42 is mounted so as to be able to slide vertically in the case of Figure 4 The lower working position shown on the left and Figure 4 The chuck 40 slides between the upper non-working position shown on the right. In the lower working position, the chuck 40 can be fixedly connected to the neck 16 of the preform 12A, and in the upper non-working position, the chuck 40 retracts back into the sleeve 48 to above the unloading surface 50 to allow the chuck 40 to disengage from the neck 16 of the preform 12A, while the preform is still locked outside the sleeve 48 by blocking the unloading surface 50.

[0079] Without limitation, the chuck 40 is controlled to its inoperative position by a cam device (not shown) and is urged to its operative position by an elastic member 52 , here a spring, vertically interposed between the chuck 40 and the link 46 .

[0080] The rotation of the chuck 40 about the main axis "Z1" of the preform 12A is controlled here by a pinion 54, which is arranged here at the upper end of the shaft 42 above the chain ring 46. The pinion 54 is intended to cooperate with a rack 56, which is arranged on at least a section of the heating path 36.

[0081] In a variant of the invention not shown, the rotation of the chuck 40 is controlled by a separate motor, which is carried on the chain ring 46. This rotation is then controlled by an electronic control unit.

[0082] Each link 46 here carries a single swivel 38. The links 46 are mounted so as to be articulated to one another in a chain around the main axis "Z3" by means of hinges 58. The links 46 are thus assembled to form a closed chain 37.

[0083] The chain 37 meshes around a first guide wheel 60 and a second guide wheel 62, each of which is rotatably mounted around a vertical axis "Z4, Z5". At least one of the guide wheels 60, 62 is driven in a clockwise direction by at least one motor (not shown) so as to drive the chain 37.

[0084] Each swivel 38 here moves continuously, i.e. uninterruptedly, along a closed loop. A complete revolution of the swivel 38 along the closed loop will be referred to hereinafter as a "cycle". Figure 3 A useful section indicated by a bold line in the figure forms a heating stroke 36, along which each turntable 38 is intended to load a preform 12A, and another unloaded section through which the turntable 38 passes unloaded completes the circuit. On the heating stroke 36, each turntable 38 transports a preform 12A from a preform 12A loading point 64 to a transfer point 66 for transferring the preform 12A to the forming station 26. The loading point 64 and the transfer point 66 are arranged on the periphery of the first guide wheel 60.

[0085] The preforms 12A are successively transported to the loading point 64 by upstream transport means, for example by means of a notched wheel 68. At the loading point 64, each clamp 40 engages in the neck 16 of a preform 12A transported by the notched wheel 68. The notched wheel 68 is provided with notches 69 on its periphery, each notch being intended to support a preform 12A.

[0086] At the end of the heating stroke 36 , the hot preforms 12A are transferred to downstream conveying means such as a transfer wheel 70 , which is here equipped with grippers 72 intended to grip each preform 12A by its neck 16 . Figure 4 The control fork 74 shown controls the swivel seat 38 towards its rest position, and the control fork is carried here by the first guide wheel 60. Each control fork 74 is mounted vertically and slidably. The sliding of each control fork 74 is controlled, for example, by a cam (not shown). The first guide wheel 60 more particularly comprises a plurality of forks 74 at its periphery. The groove 76 of each swivel seat 38 is intended to engage with the fork 74 to control its sliding, as shown in FIG. Figure 4 shown.

[0087] In the unloaded section, the swivel 38 moves unloaded from the transfer point 66 to the loading point 64. The unloaded section is arranged on the chain segment "B1" of the chain 37 meshing around the first guide wheel 60.

[0088] The heating path 36 includes at least one working section and at least one rest section, along which the body 14 of the preform 12A is directly exposed to the heating element 12A. Figure 3 The heating radiation of the heating member 22 is indicated by the lightning arrow in the figure, while the main body 14 of the preform 12A is not exposed to the heating radiation of the heating member 22 along the rest section.

[0089] exist Figure 3 In the example, the heating station 20 comprises an upstream working section "H1", sometimes called the entry section, and a downstream working section "H2", sometimes called the distribution section, which are formed by two straight chain sections of the conveyor chain 37, which are tensioned between two guide wheels 60, 62. The heating means 22 are arranged along these two working sections "H1, H2" so that the body 14 of the preform 12A passing through these working sections "H1, H2" is exposed to the heating radiation. When passing through the heating working sections "H1, H2", the preform 12A is usually driven to rotate around its main axis "Z1" to allow the body 14 of the preform 12A to be heated over its entire circumference. For this purpose, each working section "H1, H2" comprises a rack 56 for driving the swivel 38 in rotation.

[0090] Here, the heating path 36 has three resting sections along which the body 14 of the preform 12A is not exposed to the heating radiation emitted by the heating means 22. Here, no heating means are arranged along the resting sections.

[0091] The first upstream rest section P1 is arranged between the loading point 64 and the upstream working section H1 . Therefore, the first rest section P1 is located on the chain section of the chain 37 that is engaged with the first guide wheel 60 .

[0092] The second intermediate rest section P2 is interposed between the upstream working section H1 and the downstream working section H2 . The second intermediate rest section P2 has a circular arc shape, in particular, because it extends over the chain section of the chain 37 that meshes around the second guide wheel 62 .

[0093] The third downstream rest section P3 is arranged between the downstream end of the downstream working section H2 and the transfer point 66. Therefore, the third rest section P3 is located on the chain section of the chain 37 that is engaged with the first guide wheel 60.

[0094] A protective member (not shown) is used to protect the neck 16 of the preform 12A from heat radiation so as to keep the neck 16 at a temperature lower than the glass transition temperature.

[0095] During the entire heating stroke 36, the orientation of each swivel 38 is controlled. Figure 4 In the embodiment shown in the figure, each swivel seat 38 here comprises a crank pin 78, which is arranged eccentrically with respect to the axis of rotation "Z3". The crank pin 78 is used to allow the swivel seat 38 to be correctly oriented by passing between a set 80 of two converging bevels arranged along the path of the swivel seat 38 when passing from each rest section P1, P2, P3 to the next working section H1, H2. The crank pin 78 is thus automatically positioned upstream with respect to the direction of movement of the swivel seat 38. At the exit of this set 80 of converging bevels, the pinion 54 is directly meshed with the rack 56, so that the orientation of the swivel seat 38 can be easily inferred from its position along the heating stroke 36 as long as the pinion 54 is meshed with the rack 56.

[0096] When the swivel seat 38 reaches the first guide wheel 60, the crank pin 78 is received between two fingers 82 of an orientation device 84 carried by the first guide wheel 60. The orientation device 84 also includes a motor 86 that allows the fingers 82 to rotate about the axis "Z3" relative to the first guide wheel 60 so as to be able to orient the swivel seat 38 about its axis "Z3", as shown in FIG. Figure 5 and Figure 6 Therefore, the first guide wheel 60 comprises a plurality of orientation devices 84, which are arranged at the periphery so that each swivel 38 is loaded on the meshing chain segment by a certain orientation device 84.

[0097] In a variant of the invention that is not shown, the rack and / or the orientation device can be replaced by a separate motor for driving in rotation the swivel seat 38 carried by each chain link 46 .

[0098] The parameter settings of each heating element 22 can be controlled so as to heat some parts of the body 14 of the preform 12A more or less. The adjustable parameters include, for example, the position of each heating element 22 relative to the heating stroke 36, and / or the power of the radiation emitted by each heating element 22, and / or the opacity of the reflector positioned facing some of the heating elements 22. For example, these parameters are automatically controlled by an electronic control unit. In this way, by simultaneously controlling the heating radiation power and the orientation of the swivel 38 at any point in the heating stroke 36, the body 14 of the preform 12A can be heated according to a so-called "preferred" heating profile, thereby then allowing the finished container 12B to have a non-axisymmetric shape during the forming process.

[0099] The preform 12A thus heated is then transferred by a transfer wheel 70 to the forming table 30 of the forming station 26, which transfers the preform to another conveying device directly downstream, here formed by a second transfer wheel 87, which is itself equipped with a clamp 89 for individually clamping each preform 12A.

[0100] In a variant of the invention that is not shown, a single transfer wheel transports the preforms between the heating station and the shaping station.

[0101] As mentioned above, the forming station 30 is carried by the rotating turntable 28. During production, the turntable 28 rotates continuously. Therefore, it can move the preform 12A / container 12B along the forming stroke forming a section of the production path 13.

[0102] Figure 7 Such a forming station 30 equipped with a forming station 26 is shown in more detail in FIG. As is known, the forming station 30 has a forming mold 88, which is generally made in two or three parts that are movable relative to each other, so as to allow the clamp 89 of the directly upstream conveying device, here the second transfer wheel 87, to introduce the hot preform 12A into the mold cavity 90 formed in this mold 88, and to allow the container 12B to be removed from the mold 88 after the forming process. When the parts of the mold 88 are assembled, the mold 88 has a generally planar upper surface 92, which is traversed by a through hole 94 with a vertical axis Z6 that opens vertically into the mold cavity 90. Each mold 88 thus forms a separate support member for a preform 12A, allowing the preform to be conveyed along the forming stroke.

[0103] The molding station 30 also has an injection device 96 for injecting a pressure molding fluid such as air. The injection device 96 has a nozzle 98, which is arranged vertically above the mold 88, and the nozzle is used to be controlled to slide vertically downward along the axis Z6 passing through the hole 94 to the opposite side of the neck 16 of the preform 12A to inject pressurized air therein, thereby forcing the material of the body 14 of the preform 12A to deform and conform to the shape of the mold cavity 90.

[0104] According to a known design of the injection device 96, the nozzle 98 is tubular. The nozzle can be vertically movable in a fixed nozzle holder assembly 100 of the forming table 30. The nozzle 98 is passed through along the axis Z6 by a stretch rod 102, which is vertically controlled by an actuator, a motor or a cam / roller device (not shown) so that the stretch rod engages in the preform 12A and guides the vertical deformation of the preform during the forming process, especially the blow-molding process.

[0105] In the example, the forming table 30 is provided with a bell-shaped nozzle 98, which is similar to the nozzle described in French patent FR-2764544. Thus, the nozzle 98 is provided at its lower end with a bell-shaped member 104, which is open at its lower end so as to Figure 8 The seal around the neck 16 of the preform 12A is shown bearing against the upper surface 92 of the mold 88, rather than against the neck 16 of the preform 12A. Once the bell 104 bears against the mold 88, the nozzle 98 is in sealed communication with the interior of the preform 12A to inject pressurized gas therein.

[0106] In a variant that is not shown, the lower end of the nozzle 98 is in sealing contact with the neck 16 of the preform 12A in order to inject the pressurized gas.

[0107] The nozzle 98 , and thus the bell 104 , can be positioned vertically between two extreme positions.

[0108] exist Figure 7 In the embodiment shown in FIG. 1 , the nozzle 98 is in a first extreme position, called the extreme retracted position, in which it allows the preform 12A to be loaded into the mold 88 and then the container 12B to be unloaded once it has been formed. In this extreme retracted position, the bell 104 is separated vertically above the upper surface 92 of the mold 88.

[0109] Figure 8 The nozzle 98 is shown in a second extreme position, referred to as the extreme working position, in which the bell 104 bears sealingly against the upper surface 92 of the mold 88 , covering the through hole 94 and the neck 16 .

[0110] The movement of the nozzle 98 between its two extreme positions can be controlled in different ways. The sliding of the nozzle 98 is controlled, for example, by a linear motor 105. In a variant of the invention not shown, the sliding of the nozzle is controlled by means of a stepped pneumatic actuator system.

[0111] The nozzle 98 has a drive member 114 which allows the preform 12A to be firmly held in its seated position in the mold 88 during the molding process, in particular when a pressurized molding fluid is introduced into the preform 12A. The drive member 114 is separated vertically from the preform 12A when the nozzle 98 is in its extreme retracted position. The drive member 114 is used to contact the seated preform 12A when the nozzle 98 is moved vertically from its extreme retracted position to a determined intermediate position between its two extreme positions, called the intermediate orientation position, such as Fig. 9 As shown, in this position, the bell 104 is close to the upper surface 92 of the mold 88, but is not in contact with the upper surface 92 of the mold 88. In this way, at least a lower section of the neck 16 of the preform 12A remains visible from the outside.

[0112] The forming stations 30 are arranged on a common circular path centered on the central axis Z2. Therefore, during their movement, the forming stations 30 continuously carry the hollow bodies 12 along a circular arc-shaped forming stroke forming a section of the production path 13. Typically, the circular path of the forming stations 30 is divided into four different sectors, such as Fig.10 shown.

[0113] In a first sector S1, referred to as the unloading and loading sector, the nozzle 98 is controlled in its extreme retracted position to allow the introduction of the preform 12A into the mold 88, for example, the preform 12A being carried by the gripper 89, as shown in FIG. Figure 7 shown.

[0114] Then, in the second sector S2 arranged directly downstream of the first sector S1 , the nozzle 98 is controlled in its intermediate orientation position. The clamp 89 is now withdrawn.

[0115] In the third blowing sector S3 , the nozzle 98 is in its extreme working position, so as to allow the preform 12A to be formed into a finished container.

[0116] At the end of the third sector S3, the forming table 30 enters the fourth inspection sector S4, in which the nozzle 98 is controlled to an intermediate directional position.

[0117] After leaving the fourth sector S4, the forming station 30 directly returns to the first sector S1, and the nozzle 98 is controlled in the first sector to its extreme retracted position so that the finished container can be taken out and a new preform 12A can be inserted to start a new forming cycle.

[0118] As explained in the preamble, in some applications, the hollow body 12 must be oriented before processing. For example, the preform 12A, which has been heated according to a "preferred" heating profile, should be oriented in the forming station 30 to conform to the shape of the mold cavity. To this end, Fig.11 As shown, it is known to produce at least one angular mark 106 on the neck 16 of the preform 12A, since the neck 16 does not undergo any transformation.

[0119] The angular mark 106 is formed in an undulating shape, for example, as a convex pin or a cutout made on the neck 16. It can also be a mark made by local heating or printing.

[0120] The angular deviation α between the current angular position of the preform 12A and the reference angular position is determined, for example, in the region of at least one so-called measuring region 107 of the production path 13. The angular deviation α is thus an angle measured about the main axis Z1 of the neck 16 of the hollow body 12. The reference angular position corresponds to the angular position that the preform 12A should assume relative to its support member about its main axis Z1 when the preform 12A passes through the heating stroke, so that the heating profile coincides with the angular mark 106. The reference angular position corresponds to the angular position that the hollow body 12 should assume relative to the mold about its main axis Z1 when the hollow body 12 passes through the forming stroke, so that the angular mark 106, and thus the heating profile, coincides with the shape of the mold cavity 90.

[0121] In the context of the present patent, the angular deviation α is defined here as being oriented between −180° and +180°, the value 0° corresponding to an angular position of the hollow body 12 corresponding to a reference angular position of the hollow body.

[0122] The manufacturing device 10 here has a plurality of measurement areas 107. In the following, reference will be made in a general manner to Fig.12 and13 The structure and operation of the assay area 107 is described, and this description is applicable to all assay areas 107 of the manufacturing apparatus 10. Each assay area 107 is identified below by a reference numeral 107 with a letter associated with each of the assay areas.

[0123] Each measuring area 107 is equipped with a group of at least one camera 108, which is used to take a picture of the neck 16 of the hollow body 12. The camera 108 is, for example, a video camera or a digital sensor camera. The camera 108 is arranged to capture a digital image that can display the angular mark 106 set on the neck 16 of the hollow body 12. Therefore, an illumination device (not shown) for illuminating the neck 16 can be configured to ensure a clear image of the neck 16 during the image capture. The illumination device is, for example, integrated into the camera 108.

[0124] The camera device 108 is designed to automatically transmit an image of the neck 16 of the hollow body 12 to the electronic control unit 110 in order to be able to carry out a determination step E1 for determining the angular deviation α of the determined hollow body 12 relative to a reference angular position in the determination region 107 of the production path 13 .

[0125] The determination step E1 comprises a first imaging phase E1-1 for capturing at least one image of the neck 16 of the hollow body 12 on the support member by means of an imaging device 108 which is arranged at a predetermined position relative to the production path 13 during the imaging. Such an image is, for example, Fig.14 and 15 Shown in.

[0126] The field of view of the camera 108 is generally conical in shape, and has a main axis called the camera axis X1. The camera 108 is arranged so that when taking pictures, its camera axis X1 is oriented toward the neck 16 to capture an image showing the outer surface 17 of one side of the neck 16. Fig.12 and 13 In the example shown, the camera axis X1 is arranged generally radially with respect to a main axis Z1 of the neck 16 of the hollow body 12 at the same height of the neck 16 .

[0127] In a variant of the invention that is not shown, the camera axis X1 has another orientation, for example it is arranged coaxially with the main axis Z1 of the neck 16 of the hollow body 12 .

[0128] The camera device 108 is fixedly mounted relative to the ground, and its camera axis X1 is oriented toward a fixed aiming point T of the production path relative to the ground. The aiming point T corresponds to the position where the neck 16 of the hollow body 12 entering the measuring area 107 is located.

[0129] Thus, the camera device 108 is adapted to automatically capture an image of the neck 16 in a “flash” manner along the camera axis X1 of the camera device 108 when the neck 16 passes through the aiming point T. Thus, a single set of at least one camera device 108 is sufficient to capture an image of the neck 16 of each hollow body 12 in the queue when the hollow body 12 passes through the measuring area 107.

[0130] When the measurement area 107 is covered by only a single camera device 108 oriented radially to the camera axis X1, the hollow body 12 is preferably provided with at least two radially opposite angular markings 106 to ensure that at least one of the angular markings 106 appears in the captured image. Figures 11 to 15 In the example shown, the neck 16 of the hollow body 12 has four evenly distributed angular markings 106. When the heating profile has a pattern that repeats every 90°, as is the case here, these four angular markings can remain identical.

[0131] In a variant, when the camera axis X1 is arranged coaxially with the main axis Z1 of the neck 16, the neck 16 may have only a single angular mark 106, which is visible from a single camera device located on the main axis Z1 of the neck 16, for example when the angular mark 106 is located on the hoop.

[0132] In a variant, the measuring area 107 has a set of a plurality of camera devices 108, which are fixedly mounted relative to the ground. The camera axis X1 of each camera device 108 is oriented toward the main axis Z1 of the neck 16 of the hollow body 12, which passes through the aiming point T. This allows each camera device 108 to simultaneously capture images of the same neck 16 at different angles. Thus, when these camera devices 108 are arranged to cover together the entire cylindrical outer surface 17 of the neck 16, the neck 16 can be provided with only one single angular marking 106.

[0133] The camera device 108 may transmit the captured image of the neck 16 to the electronic control unit 110 , for example, via a wired connection or via an appropriate electromagnetic signal.

[0134] During the second processing phase E1-2 of the determination step E1, each image captured by the set of at least one camera device 108 is subjected to information processing in order to detect the angular position of the angular markings 106 visible on the image relative to a reference angular position. To this end, the electronic control unit 110 is equipped with image processing software that allows the recognition of the angular markings 106 present on the image.

[0135] As soon as the position of the angular marking 106 is identified on the image, a third phase E1 - 3 is initiated, during which the angular deviation α of the hollow body 12 is determined by the electronic control unit 110 .

[0136] like Fig.14 and15 As shown, since the position of the camera device 108 is fixed, the position where one of the angular marks 106 on the image should be located in order to make the hollow body 12 in its reference angular position, that is, the reference point 106R, is unchanged. The reference point 106R is determined before the method is implemented. The electronic control unit 110 calculates the angular deviation α based on the lateral distance between the reference point 106R and the current position of the angular mark 106 identified on the image. Therefore, based on the current position of the angular mark 106 relative to the reference point 106R, which is on the right or left side as shown in the figure, the electronic control unit 110 determines the direction of the angular deviation α relative to the reference position.

[0137] Figure 1 The production plant 10 shown has at least two such measuring areas 107 which are equipped with such camera devices 108 .

[0138] Just before the preform 12A is loaded by the turret 38 , the first measuring area 107A is arranged at the periphery of the notched wheel 68 .

[0139] Then, during the correction process, the position of each preform 12A is individually corrected in accordance with the angular deviation α measured for the preform 12A in a first correction area 112A arranged downstream of the first measurement area 107A.

[0140] The first calibration area 112A is arranged on the first resting section P1 of the heating stroke after the preform 12A is loaded by the rotary table 38. Thus, the orientation device 84 of the first guide wheel 60 can correctly orient the rotary table 38 so that the angular position of the crank pin 78 coincides with the determined angular position of the angular mark 106 of the preform 12A. Thus, this makes it possible to match the heating profile of the preform 12A with the angular mark 106.

[0141] The second measuring area 107B is arranged in the second angular sector S2 just after the preform 12A is placed in the mold 88. Therefore, after the preform 12A is placed in the mold 88, the orientation of the preform 12A can be corrected in the second correction area 112B during the correction process so that the position of the angular mark 106 and thus the position of the heating profile exactly corresponds to the shape of the mold cavity 90, wherein the second correction area 112B is arranged downstream of the second measuring area 107B, here always in the second angular sector S2.

[0142] The angular position of the preform 12A is corrected, for example, by means of a rotating nozzle 98 , as described in document EP 1 261 471 B1.

[0143] The drive member 114 is mounted rotatably relative to the mold 88 about the axis Z6 so as to be able to drive the preform 12A in rotation about its main axis Z1 when it is in the intermediate orientation position. The drive member 114 can be driven in a controlled manner in both directions by an electric device for driving rotation, such as a motor 116. The motor 116 is automatically controlled by the electronic control unit 110, such as Fig. 9 shown.

[0144] In a non-limiting example, the drive member 114 is connected to the bell 104 and rotates integrally around the axis Z6, which can rotate relative to the nozzle 98 around the axis Z6, and is fixed to the lower end of the nozzle. On the contrary, the bell 104 is fixedly connected to the nozzle 98 in the vertical direction. When the nozzle 98 moves from the intermediate orientation position to the extreme working position, the drive member 114 can slide vertically relative to the assembly. For example, the drive member 114 is guided by the inner groove of the bell 104 and slides in the bell 104, and the inner groove also ensures the integral rotation of the bell 104 and the drive member 114 around the axis Z6.

[0145] When the nozzle 98 is in Fig. 9 In the intermediate orientation position shown, the nozzle can be driven to rotate by a drive device. The drive device mainly includes a motor 116 (and its control module), which controls the rotation of a pinion 118, and the axis Z7 of the pinion 118 is parallel to the axis Z6. Here, the motor 116 is installed to be fixedly connected to the nozzle holder assembly 100.

[0146] The bell 104 has an external gear 120 which meshes with the pinion 54 so that the motor 116 can rotate the bell 104 and thereby the drive member 114 .

[0147] The operation of the manufacturing apparatus 10 will now be described with respect to a specific preform 12A.

[0148] When the manufacturing device 10 produces a container 12B, the preform 12A is first loaded by the notch of the notch wheel 68. The angular position of the preform 12A is measured in the first measurement area 107A. Then, before the loading point 64 of the heating station 20 loads the relevant preform 12A, each turntable 38 is oriented by the orientation device 84 in the first correction area 112A according to the measurement result of the angular deviation α of the preform 12A made in the first measurement area 107A, so that the angular position of the turntable 38 is consistent with the angular position of the preform 12A. Then, the preform 12A is transported by the relevant turntable 38 along the heating stroke 36. During the working sections H1, H2 of the preform 12A passing through the heating stroke 36, the body 14 of the preform 12A is heated. Then, when the preform 12A reaches the transfer point 66 along the production path 13, the preform is loaded by the associated gripper 72 of the transfer wheel 70, which then transfers the preform 12A to a gripper 89 of a conveyor. The preform 12A is then placed by the gripper 89 in the mold 88 of the associated forming station 30. The gripper 89 is designed to prevent the preform 12A from rotating about its main axis Z1, so as to keep the preform 12A closest to its reference angular position.

[0149] However, it often happens that the preform 12A slips when it is transferred from one conveyor to another downstream of the heating station 20. In addition, the preform 12A is free to rotate around its main axis Z1 in the mold 88 until it is locked by the drive member 114. In order to be able to correct this slip, the angular deviation α of the preform 12A relative to its reference angular position is measured in the second measurement area 107B with the aid of the angular markings 106 when the preform 12A is first placed in the mold 88.

[0150] Downstream of the second measuring zone 107B, in a second correction zone 112B, the angular position of the preform 12A is corrected by means of the rotating nozzle 98 as a function of the angular deviation α measured for said preform 12A in the second measuring zone 107B.

[0151] This manufacturing device 10 allows obtaining containers 12B of good quality by ensuring that the heating profile of the preform 12A conforms well to the shape of the mold cavity 90. However, the duration of each correction process for correcting the position of the preform 12A is proportional to the value of the angular deviation α to be corrected in the second correction zone 112B. The production throughput is thus limited by the correction process.

[0152] In addition, sometimes the heating profile deviates slightly from the position of the angular mark 106. This may be caused by the slippage of the preform 12A between the first measurement area 107A and the preform loaded by the swivel 38. Although this error is generally very small, the quality of the finished container 12B can be further improved by reducing the deviation angle α by a small amount. In fact, the tolerance on the angular deviation is allowed, that is, when the angular deviation is within a certain range, for example, between -5° and +5°, it is considered that the influence of the angular deviation on the quality of the obtained finished container is negligible. Therefore, by reducing the angular deviation obtained for most preforms 12A to within the tolerance range, most of the correction steps for correcting the orientation of the preform can be avoided in theory.

[0153] The inventors have found that in certain measurements, the value of the angular deviation α observed in the measurement area 107 arranged downstream of the first measurement area 107A can be reduced by averaging. By considering that the angular deviations α of different preforms in a series of preforms are distributed according to a curve, such as a Gaussian curve, the angular deviations α are arranged on both sides of the average value αM, such as Fig.16 and 17 The tolerance area is shown as a hatched line on Fig.16 and 17 middle.

[0154] When the average value αM is greater than a certain threshold value in absolute value, this means that the angular deviations of most preforms are not within the tolerance range, such as Fig.16 shown.

[0155] By choosing to compensate for the angular orientation of all preforms upstream to produce a mean value αM equal to 0°, as Fig.17 As shown, the angular deviation α applied during the subsequent correction process will be reduced overall. This will therefore shorten the total duration of the correction process. When the angular deviations of most preforms fall within the tolerance range, the correction process for these preforms can even be completely eliminated.

[0156] The present invention proposes to improve the quality of the container 12B and increase the production flow by means of a method for adjusting the angular position of the preform 12A in the manufacturing device 10. Fig.18 As shown, the method according to the present invention has:

[0157] a first determination step E1 for determining, in a determination zone 107 of the production path 13 , an angular deviation α of at least one determined preform 12A relative to a reference angular position; and

[0158] - A second compensation step E2, used to compensate the angular position of the subsequent preform 12A in the compensation area 122 arranged upstream of the measurement area 107 during the compensation process, during which the angular orientation of the subsequent preform 12A is modified with an updated compensation angle α1 so as to reduce the angular deviation α of the preform 12A in the measurement area 107, wherein the updated compensation angle depends on the angular deviation α measured for the at least one determined preform 12A during the first measurement step E1 and the current compensation angle α0.

[0159] The first determination step E1 is carried out in three stages E1-1, E1-2 and E1-3 as described above.

[0160] In the first iteration of the method, the current compensation angle α0 is initialized to 0°.

[0161] At subsequent iterations, the current compensation angle α0 is set equal to the updated compensation angle α1 calculated at the immediately preceding iteration of the method.

[0162] Therefore, the adjustment method does not simply correct the angular position of the hollow body 12 in the correction area 112 located downstream of each measurement area 107, but can predict the angular deviation α of the subsequent hollow bodies 12 in the queue in the compensation area 122 to reduce the correction required in the correction area 112.

[0163] The angular deviations α of the hollow bodies 12 in a series of hollow bodies follow a random distribution. Therefore, it is impossible to completely eliminate the angular deviations α observed in each measurement area. Instead, the present invention seeks to reduce the mean value αM of the angular deviations observed in some measurement areas 107. The mean value αM of the angular deviations is traditionally defined as the sum of the angular deviations α measured for the series of preforms 12A divided by the number of hollow bodies 12 in the series.

[0164] In the second compensation step E2 , in the first phase E2 - 1 , the mean value αM of the angular deviations measured for each hollow body 12 of the series of hollow bodies 12 is calculated by dividing the sum of the angular deviations by the number of hollow bodies 12 . The mean value αM is calculated by the electronic control unit 110 .

[0165] In order to obtain a mean value αM representative of the distribution of the hollow bodies 12, it is of course possible to exclude isolated values ​​of angular deviations α that are too far from the mean value αM established in the previous iteration of the method, so that these values ​​of angular deviations α judged to be unexpected are not taken into account. In fact, these isolated values ​​of angular deviations α risk falsifying the mean value αM calculated by the electronic control unit.

[0166] Then, in the second stage E2 - 2 , an updated compensation angle α1 is calculated according to the calculated average value αM and the current compensation angle α0 .

[0167] For this purpose, at each iteration, the mean value αM calculated based on the measurement results performed in the measurement step E1 is subtracted from the current compensation angle α0.

[0168] Therefore, when the average value αM of the angular deviation of each hollow body 12 in a series of at least two consecutively determined hollow bodies 12 measured in the first determination step E1 is greater than a certain threshold value, for example greater than 0° in absolute value, the value of the current compensation angle α0 is modified in the second compensation step E2.

[0169] Then, during the third phase E2 - 3 , the orientation of the subsequent hollow body 12 is modified by the updated compensation angle α1 .

[0170] The method is iterated in a loop so that the current compensation angle α0 is adjusted at each iteration. In the fourth stage E2-4, the updated compensation angle α1 of the previous iteration is stored and used again as the current compensation angle α0 at the next iteration. Thus, the current compensation angle α0 is regularly modified so as to approach a new average value αM of 0°.

[0171] For example, when the last hollow body 12 of the previous series leaves the measurement area 107, the average value αM is calculated for a new series of hollow bodies.

[0172] In a variant, the mean value αM is calculated smoothly, ie a new iteration of the method is started before the previous iteration has ended. This allows the electronic control unit to calculate a smoothed mean value αM of the angular deviation. Thus, a hollow body 12 can belong to at least two different series of hollow bodies 12.

[0173] Several embodiments of the present invention are described below. These embodiments can be implemented individually or in combination on the same manufacturing device 10.

[0174] According to a first embodiment of the invention, a first compensation area 122A is arranged on the heating stroke 36 during the period when the preform 12A is supported by the swivel 38. The first compensation area 122A is arranged in particular on the upstream stop section P1. This allows the position of the preform 12A to be compensated before the start of heating the preform. Here, the first compensation area 122A is formed by the first correction area 112A. The compensation of the angular position of the preform 12A is performed by rotating each swivel 38 by one of the orientation devices 84 when the preform passes in the first compensation area 122A.

[0175] According to this first embodiment, the measuring step E1 is carried out in a third measuring area 107C, which is arranged downstream of the first compensation area 122A on the heating path 36. Since the orientation of the swivel 38 and thus of the preform 12A is controlled along the entire heating path 36, the third measuring area 107C can be arranged downstream of the first compensation area 122A at any part of the heating path 36. In the example, the third measuring area 107C is arranged on the downstream stop section P3. In a variant, the third measuring area 107C is arranged on the intermediate stop section P2. The arrangement of the third measuring area 107C on the stop sections P2, P3 of the heating path 36 makes it possible in particular to avoid exposing the camera device 108 to the heat generated by the heating member 22.

[0176] The compensation step E2 is performed, for example, in conjunction with a correction process of the angular position of the preform 12A. In this case, for each preform, the electronic control unit 11 sums S the correction angle measured for said preform 12A in the first measurement area 107A and the updated compensation angle α1 calculated based on the results of the measurements of the preceding series of preforms 12A in the third measurement area 107C. Thus, at the first compensation area 122A, which also forms the first correction area 112A, the preform 12A is rotated by said sum S in only a single process.

[0177] The compensation method according to this first embodiment of the invention therefore allows the heating profile of each preform 12A to be optimally adapted to the angular position of the angular markings 106 .

[0178] According to a second embodiment of the invention, the second compensation area 122B is arranged on the heating stroke 36 during the period when the preform 12A is supported by the swivel 38. The second compensation area 122B is arranged in particular on the downstream rest section P3 just before the transfer of the preform 12A to the first transfer wheel 70 and after the heating of the preform 12A is completed. This makes it possible to compensate the position of the preform 12A after the heating of the preform is completed. The compensation of the angular position of the preform 12A is performed by rotating each swivel 38 using one of the orientation devices 84 when the preform passes through the second compensation area 122B.

[0179] According to this second embodiment, the measuring step E1 is carried out in a second measuring area 107B which is arranged in the forming station 26 when the preform 12A is placed in the mold 88 prior to the forming process.

[0180] The measurements carried out by the second measurement zone 107B thus allow the angular position of each preform 12A downstream to be corrected individually, but also allows the position of the subsequent preform 12A upstream to be compensated.

[0181] The compensation step E2 is therefore applied to the preforms reaching the end of the heating stroke 36 and before being transferred to the molding station 26. This allows the heating profile of the preform 12A to be best adapted to the shape of the mold cavity 90, taking into account the slight deviations that may occur when the preforms 12A are transferred differently from one conveyor to the next and when they are placed in the mold 88.

[0182] According to a third embodiment of the present invention, the third compensation area 122C is arranged on the forming station 26 upstream of the forming process.

[0183] The third compensation area 122C is arranged in particular downstream of the second measuring area 107B and upstream of the forming process. This allows the position of the preform 12A to be compensated before the start of forming the preform. Here, the third compensation area 122C is arranged on the second angular sector S2 of the forming stroke. Here, the third compensation area 122C is formed by the second correction area 112B. When the preform passes through the third compensation area 122C, the angular position of the preform 12A is compensated by rotating the drive member 114.

[0184] According to this third embodiment, the measuring step E1 is carried out in a fourth measuring area 107D which is arranged at the molding station 26 downstream of the molding process. Here, the fourth measuring area 107D is arranged in the fourth angular sector S4 when the preform 12A is transformed into a container 12B upstream of the demolding point 34. This arrangement of the fourth measuring area 107D makes it possible in particular to check whether the angular position of the preform 12A has been correctly corrected in the second correction area 107B.

[0185] The compensation step E2 is performed, for example, in conjunction with a correction process of the angular position of the preform 12A. In this case, for each preform, the electronic control unit 110 sums S the correction angle measured for said preform 12A in the second measurement area 107B and the updated compensation angle α1 calculated based on the measurement results performed on the previous series of preforms 12A in the fourth measurement area 107D. Thus, at the third compensation area 122C, which also forms the second correction area 112B, the preform 12A is rotated by said sum S in only a single process.

[0186] The compensation method according to this third embodiment of the invention therefore allows the heating profile of each preform 12A to be optimally adapted to the shape of the mold cavity 90 .

[0187] Advantageously, the method implemented according to the teachings of the present invention makes it possible to shorten the duration of the correction step for each preform in the correction zone 112 or even eliminate said correction step.

Claims

1. A method for adjusting the angular position of a hollow body (12) in a manufacturing device (10) for manufacturing containers (12B) by molding preforms (12A) made of thermoplastic material, in which the hollow bodies (12) are moved in a row along a production path (13) by means of separate support members, each support member being equipped with a device for rotating the hollow body (12) about a hollow body axis (Z1), the method comprising a first measuring step (E1) for measuring an angular deviation (α) of at least one determined hollow body (12) relative to a reference angular position in a determined measuring area (107B, 107C, 107D) of the production path (13), It is characterized in that The method comprises a second compensation step (E2) for compensating the angular position of a subsequent hollow body (12) in a compensation area arranged upstream of a measuring area (107B, 107C, 107D), wherein during the second compensation step, the angular orientation of the subsequent hollow body (12) is modified by an updated compensation angle (α1) in order to reduce the angular deviation (α) of the subsequent hollow body (12) in the measuring area (107B, 107C, 107D), wherein the updated compensation angle depends on the angular deviation (α) measured for the at least one determined hollow body (12) during the first measuring step (E1) and on a current compensation angle (α0).

2. The method according to claim 1, characterized in that When the average value (αM) of the angular deviations of each hollow body (12) in a series of at least two consecutively determined hollow bodies (12) measured in the first determination step (E1) is greater than a determined threshold value in absolute value, the value of the current compensation angle (α0) is modified in the second compensation step (E2).

3. The method according to claim 2, characterized in that In the second compensation step (E2), an updated compensation angle (α1) is calculated by subtracting a mean value (αM) of a series of determined angular deviations of the hollow body (12) from the current compensation angle (α0).

4. The method according to claim 3, characterized in that The method iterates in a loop, and the current compensation angle (α0) is formed by the updated compensation angle (α1) of the previous iteration.

5. The method according to claim 4, characterized in that At the first iteration, the current compensation angle (α0) is initialized to 0°.

6. The method according to any one of the preceding claims, characterized in that The manufacturing device (10) has a heating station (20), the heating station is provided with a conveying device (24), the conveying device is equipped with a supporting member called a swivel (38), each swivel can individually convey a preform (12A) along a heating path forming a section of a production path (13), each swivel can rotate the preform (12A) around the preform axis, while the preform (12A) is supported by the swivel (38), a compensation area is arranged on the heating path, and the angular position of the preform (12A) is compensated by rotating each swivel (38) by the updated compensation angle (α1) when the preform passes through the compensation area.

7. The method according to claim 6, characterized in that The conveying device (24) has a chain (37) formed by a swivel (38), which is guided by two guide wheels, and the compensation area is located on the chain section of the chain (37) that meshes with one of the two guide wheels (60).

8. The method according to claim 7, characterized in that The compensation zone is located on the chain section (37) that engages the guide wheel (60) downstream of the loading point (64) where the preforms (12A) are transferred from the upstream conveyor (68) before the heating of the preforms (12A) begins.

9. The method according to claim 8, characterized in that The measuring area is located in the heating station (20) on the chain section that engages with the guide wheel (60) upstream of the transfer point (66) at which the preform (12A) is transferred to the downstream conveying device (70) in the direction of the forming station (26) after the preform (12A) has been heated.

10. The method according to claim 9, characterized in that The manufacturing device (10) has a forming station (26) in which each hollow body (12) moves along a forming stroke forming a section of a production path (13), and each preform (12A) undergoes a forming process along the forming stroke to form a final container (12B).

11. The method according to claim 7, characterized in that The compensation area is located on the chain section (37) that engages with the guide wheel (60) upstream of the transfer point (66) that transfers the preform (12A) to the downstream conveying device (70) in the direction of the forming station (26) after the preform (12A) has been heated.

12. The method according to claim 11, characterized in that The manufacturing device (10) has a molding station (26), in which each hollow body (12) moves along a molding stroke forming a section of a production path (13), and each preform (12A) undergoes a molding process to be formed into a final container (12B) along the molding stroke; and the measuring area is located in the molding station (26) arranged downstream of the heating station (20) before the start of the molding process.

13. The method according to claim 10, characterized in that The compensation area is positioned along the forming stroke before the forming process begins.

14. The method according to claim 13, characterized in that The measuring area is located in the forming station (26) along the forming path after the forming process is completed.

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