Method for automatically checking the presence of preform retaining components in the heating station

Abstract

The present invention relates to a method for inspecting holding members (30) in a heating station (10), the heating station being equipped with a device (28) for conveying a preform (12), comprising: a plurality of movable supports (32) circulating in a closed loop; holding members (30) for individually holding the preform (12) by means of their necks (16), each holding member (30) being carried by a movable support (32); characterized in that the method comprises: a step (E1) of moving the movable supports (32) to successively bring the movable supports to a collection area (Z1); a step (E2) of acquiring an image of each individual holding member (30) in the collection area (Z1); and a step (E3) of automatically checking the presence of the holding member (30) in each captured image.

Description

Technical Field

[0001] This invention relates to a method for automatically checking the presence of a holding member in a heating station for holding preforms made of thermoplastic material. The heating station is equipped with a conveying device for conveying the preforms along a heating tunnel. The conveying device includes:

[0002] - Multiple movable support components;

[0003] - Retaining members are used to individually retain the preform through the neck of the preform. Each retaining member is supported by a movable support and is detachably fixed to its respective movable support. Background Technology

[0004] Equipment for mass-producing containers from preforms is known. Preforms are typically obtained by injection molding of thermoplastic materials. The preforms are then cooled and stored so that they can be later transformed into final containers.

[0005] Preforms typically include a body that is formed into the final container during operations such as blow molding or stretch blow molding to shape the preform's walls. Preforms also include a neck that has already been molded into its final shape. Therefore, it is important to protect the neck of the preform so that it is not deformed or damaged during the manufacturing process of the final container.

[0006] To allow the body of the preform to be formed during the forming step, the body wall is preheated to a temperature sufficient to make it ductile. This heating operation is performed just before the forming operation by passing the preform through a heating station.

[0007] A heating station typically includes a heating tunnel in which heating devices, such as infrared lamps, are arranged. The preform is loaded by a conveyor that moves its body through the heating tunnel. This conveyor typically includes supports that can move along the path of the preform, and holding members are mounted on the supports to individually hold the preform.

[0008] To allow for uniform heating of the preform body, the retaining member is typically designed to drive the preform to rotate about its main axis during transport. This retaining member is sometimes referred to as a "rotator".

[0009] The body of the preform becomes ductile by heating the thermoplastic material that forms the main wall of the preform, especially by heating it above the glass transition temperature.

[0010] As previously stated, the neck of the preform already has its final shape. Unlike the body of the preform, the neck is therefore kept at a temperature below the glass transition temperature to avoid deformation.

[0011] To this end, the heating station is designed such that the body of the preform is received in the “hot” part of the station formed by the heating tunnel, while the neck of the preform, which should remain relatively cool, is received in the “cold” part, which is usually located under the heating tunnel.

[0012] Of course, the hot and cold sections of the heating station are adjacent. To reduce heat exchange between the hot and cold sections, it is known to insert heat-protected girders between these sections, and the preform travels between these girders. These protective girders reduce the opening between the cold section and the heating tunnel. The protective girders are spaced apart to form travel channels, the width of which is slightly larger than the outer diameter of the preform section directly below the neck, so as to allow the preform to travel without contacting the protective girders.

[0013] These two protective stands are typically cooled by internal circulation of the heat transfer fluid to prevent heat buildup.

[0014] In addition, some manufacturing equipment includes guide frames that allow the preform to be guided rather than simply cooled. This is the case, for example, in heating stations that use laser heating devices to heat the preform body.

[0015] In addition, container manufacturing equipment is provided to allow the production of final containers of different sizes. This often results in the use of preforms of different sizes depending on the batch of containers to be produced. Therefore, when container sizes change, the equipment, especially the heating station, needs to be adapted to the dimensions of the new preforms.

[0016] This in particular means modifying the retaining member to match the neck inner diameter of the new preform specification. To this end, the retaining member is advantageously detachably secured to its movable support via a quick-release fastener.

[0017] Changing the retaining member can sometimes lead to errors. Therefore, it's possible to overlook equipping the movable support with a new retaining member, or to equip the movable support with an unsuitable type of retaining member.

[0018] This also means adjusting the bench spacing to match the width of the channel to the under-neck diameter of the new specification preform.

[0019] However, manually adjusting the channel width also takes a lot of time. Summary of the Invention

[0020] This invention proposes a method for inspecting a holding member used to hold a preform made of thermoplastic material in a heating station. The heating station is equipped with a conveying device for conveying the preform along a heating tunnel. The conveying device includes:

[0021] - Multiple movable support components;

[0022] - Retaining members are used to individually retain the preform through the neck of the preform. Each retaining member is supported by a movable support and is detachably fixed to its respective movable support.

[0023] The method is characterized by comprising:

[0024] -The step of moving the movable support to successively bring the movable support into the collection area;

[0025] -The acquisition step of acquiring an image of each individual holding member as each moving support passes through the acquisition area using an image capture device;

[0026] - An inspection step that automatically checks the presence of a component in each image by using an electronic control unit to process each image captured during the acquisition step via computer.

[0027] According to another feature of the method of the invention, when at least one retaining member is detected not to be present on the movable support during the inspection step, an alarm signal is issued by the electronic control unit.

[0028] According to another feature of the method of the invention, the retaining member is formed of a mandrel for insertion into the neck of the preform, and each retaining member is to be replaced when the preform specification is changed so that the outer diameter of the retaining member matches the inner diameter of the neck of the preform.

[0029] According to another feature of the method of the invention, the method is started after the replacement of the retaining member begins but before the heating station is put into operation.

[0030] According to another feature of the method of the present invention, the heating station includes:

[0031] - At least one pair of longitudinal platforms define a channel for the travel of the preform, and at least one longitudinal platform is laterally movable to change the width of the channel.

[0032] - At least one motorizing device for laterally moving the at least one movable longitudinal platform to adjust the width of the channel, the motorizing device being automatically controlled by an electronic control unit.

[0033] According to another feature of the method of the present invention, the method includes:

[0034] - The determination step of the outer diameter of the retaining member is automatically determined by computer processing at least one of the images captured during the acquisition step;

[0035] - The step of automatically adjusting the width of the channel by moving at least one platform according to the outer diameter determined in the determining step.

[0036] According to another feature of the method of the present invention, during the acquisition step, the image capturing device captures the profile of the holding member.

[0037] According to another feature of the method of the present invention, the image capturing device is arranged at a predetermined distance from the holding member during the image capturing operation.

[0038] Another feature of the method according to the invention is that the type of retaining member is determined by identifying visual markings carried by each retaining member.

[0039] According to another feature of the method of the present invention, in the determining step, the outer diameter of the retaining member is obtained by multiplying the width of the retaining member measured on the image by a predetermined scaling factor.

[0040] According to another feature of the method of the present invention, in the determining step, the outline of the retaining member presented on the image is compared with the outline of the retaining member stored by the electronic control unit, each stored outline being associated with an outer diameter stored by the electronic control unit. Attached Figure Description

[0041] Other features and advantages of the present invention will become apparent as you read the following detailed description, which will be understood with reference to the accompanying drawings, in which:

[0042] Figure 1 This is a schematic top view of a preform heating station to which the inspection method of the present invention can be applied.

[0043] Figure 2 It is along Figure 1 The longitudinal sectional view of section 2-2 shows the section used to pass through Figure 1 As part of the conveying device for the heating station that transports preforms, one of the retaining members is shown in the installed position, while the other retaining member is shown in the position to be installed.

[0044] Figure 3 It is along Figure 1 The transverse sectional view of section 3-3 shows Figure 1 The heating tunnel of the heating station

[0045] Figure 4 It is a schematic representation of the location Figure 1 A bottom view of the thermal protection platform next to the heating tunnel of the heating station.

[0046] Figure 5 This is a block diagram illustrating the method of the present invention. Detailed Implementation

[0047] In this description, elements with the same structure or similar function will be represented by the same reference numerals.

[0048] In this description, the longitudinal direction oriented from back to front, the lateral direction oriented from left to right, and the vertical direction oriented from bottom to top, represented by the coordinate system "L,V,T" in the figure, will be used in a non-limiting manner. The vertical direction is used as a purely geometric orientation independent of Earth's gravity.

[0049] Figure 1 The diagram shows a heating station 10, which is a manufacturing facility for producing containers by blow molding or stretch blow molding preforms 12 made of thermoplastic materials such as polyethylene terephthalate (PET). The preforms 12 travel one after another along a production path that passes through various processing stations (including the heating station) of the manufacturing facility.

[0050] like Figure 2 As shown, the preform 12 is an axisymmetric hollow body with a main axis "A" shown vertically here. The preform 12 is closed at a first axial end by a bottom 14, shown here above, and opens at the opposite axial end forming a neck 16, shown here below. Thus, the preform 12 is axially divided into a first segment extending from the bottom 14 to the beginning of the neck 16, and a second segment formed by the neck 16, the first segment generally referred to as the body 18 of the preform. At the junction of the neck and the body 18 of the preform 12, the neck 16 includes a ring 20.

[0051] Section 18 of the main body directly contacts the ring 20, as shown here. Figure 2 Shown directly above the neck 16, hereinafter referred to as the lower neck section 21. The outer diameter of the lower neck section will be referred to hereinafter as the "lower neck diameter D1" (because the preform 12 is shown here). Figure 2 and Figure 3 (The middle part is upside down and placed).

[0052] Furthermore, the neck 16 is internally defined by an inner cylindrical wall 23 having an inner diameter D2.

[0053] In a known manner, the body 18 of the preform 12 is used to be stretched during the operation of forming the final container, while the neck 16 of the preform 12 already has the shape required for the final container. For this purpose, the body 18 is used to be heated in the heating station 10 to become malleable, while the neck 16 is used to be kept warm in the heating station to prevent deformation.

[0054] Reference Figure 1 The heating station 10 includes a heating tunnel 22, which has two longitudinal sections 22a and 22b interconnected by an end bend 22c. Each longitudinal section 22a and 22b of the heating tunnel 22 is laterally defined by an inner wall 24 and an outer wall 26.

[0055] The heating station 10 also includes a conveying device 28 for conveying preforms 12 in rows along a section of the heating path that forms a production path within the heating tunnel 22. The preforms 12 are conveyed vertically along their axis "A" and with their necks 16 oriented downwards at longitudinal sections 22a, 22b and at the end bends 22c, to protect the necks 16 from heat. The main axis "A" of the preforms 12 is therefore orthogonal to their direction of travel along the heating path.

[0056] In variations not shown, the invention is also applicable to preforms conveyed by conveying with the neck upward.

[0057] exist Figure 2 The conveying device 28 is shown in more detail. It includes a plurality of movable supports 32 that circulate along a defined loop. This relates to a closed loop.

[0058] In a variant of the invention (not shown), the movable support moves along an open loop.

[0059] The conveying device 28 also includes retaining members 30 for individually holding the preform 12 through the neck 16 of the preform 12. Each retaining member 30 is carried by an associated movable support 32. Furthermore, each retaining member 30 is capable of driving the carried preform 12 to rotate about its vertical axis "A" as it passes through the heating station 10. This rotation ensures uniform heating of the body 18 of the preform 12. This assembly is also known as a "rotator".

[0060] Each retaining member 30 is mounted integrally with and rotatably connected to a shaft 31 having a vertical axis "A". The shaft 31 is mounted to rotate within a guide bearing 33 of an associated movable support, allowing rotation of the preform 12. Here, refer to... Figure 2 The retaining member 30 is mounted on the upper end of the shaft 31, which here includes a pinion 35 at its lower end. The pinion 35 is capable of engaging a rack (not shown) arranged along the path of the movable support 32 to drive its rotation.

[0061] In a variant not shown, the shaft is rotated by means of a motor mounted on a movable support.

[0062] Each retaining member 30 is formed here by a mandrel arranged coaxially with the axis of rotation "A". The mandrel can be axially inserted into the neck 16 of the container for a tight fit to ensure that the preform 12 is secured by friction with the inner cylindrical wall 23 of the neck 16. The mandrel here includes at least three segments 37, two of which are in Figure 2As can be seen in the cross-section, they are arranged around the axis of rotation "A". Each segment 37 is radially pushed outward to an expanded position by a ring 39 made of an elastomeric material, which is inserted between itself and the central portion 41 of the retaining member 30 fixed relative to the axis 31. Thus, each segment 37 can be radially pressed against the inner cylindrical wall 23 of the neck 16 to grip the preform 12 by friction. For this purpose, the portion of the retaining member 30 for tight housing within the neck 16 has an outer diameter "D3" in the expanded state, which is slightly larger than the inner diameter D2 of the neck 16 for the loaded preform 12. The outer diameter "D3" of the retaining member 30 is, for example, equal to the sum of the inner diameter "D2" of the neck 16 and a defined additional thickness "s", for example, about one millimeter.

[0063] Heating station 10 is typically designed to allow batch processing of different types of preforms 12. The inner diameter "D2" of the neck 16 may vary depending on the type. Therefore, when a new batch of preforms 12 is requested to process, with a neck 16 inner diameter "D2" that differs from that of the previous batch of preforms 12, all retaining members 30 of heating station 10 need to be modified to accommodate the new preforms 12.

[0064] For this purpose, each retaining member 30 is detachably fixed to its associated movable support 32. More specifically, the retaining member 30 is here detachably fixed to the upper axial end of the shaft 31. Figure 2 In the diagram, the left shaft 31 is shown without the retaining member 30, while the right shaft 31 is shown with the retaining member 30.

[0065] The retaining member 30 can be mounted on its associated movable support 32 by any known means, such as screwing. However, it is advantageous that the retaining member 30 is equipped with a quick-locking device 45, which allows for installation and removal without tools. This relates, for example, to a quick-locking interlocking device such as a ball lock.

[0066] In the example shown in the figure, the movable supports 32 are hinged together in pairs to form links of a closed chain 47. More specifically, the movable supports 32 are hinged together about an axis parallel to axis "A" of the preform 12 loaded by the retaining member 30. Thus, the movement of the preform 12 is achieved by the closed chain 47 of the movable supports 32.

[0067] In the variant, the movable support is formed by reciprocating transport vehicles (navettes) that circulate on a track, each of which, together with the track, forms a linear motor.

[0068] When the preform 12 is used for neck-down passage, as is the case here, the movable support 32 is also advantageously mounted to pivot relative to each other about a longitudinal axis to allow the preform 12 to be flipped during its transport. This thus allows the preform 12 to be loaded with its neck up, then heated with its neck down, and subsequently flipped again with its neck up at the outlet of the heating station 10.

[0069] Refer again Figure 1 The chain 47 is guided and moved by engaging around two guide wheels 34 and 36. Each guide wheel 34 and 36 is mounted to rotate about an associated central vertical axis “X1, X2”. The guide wheels 34 and 36 are located at the two longitudinal ends of the longitudinal sections 22a and 22b of the heated tunnel 22.

[0070] At least one of the guide wheels 34 and 36 is driven to rotate to move the retaining member 30. For example, one of the two guide wheels 34 and 36 is driven by a motor, while the other wheel, referred to as the driven wheel, is driven to rotate by a chain 47.

[0071] In this variation, each of the two guide wheels is driven to rotate by a motor, for example, a brushless motor. Both guide wheels are driven to rotate together. This advantageously allows for a reduction in tension within the chain.

[0072] In a variant not shown, the invention also applies to a conveying device comprising movable supports forming independent reciprocating transport vehicles that move along a track. For example, each reciprocating transport vehicle forms a linear motor together with the track.

[0073] The first guide wheel 34 is configured to allow loading of the cold preform 12 at a loading point 49 located upstream of the first longitudinal section 22a. The cold preform 12 is delivered by the input wheel 38. The first guide wheel 34 is also configured to allow unloading of the hot preform 12 at an unloading point 51 located downstream of the second longitudinal section 22b and upstream of the loading point 49. The hot preform 12 is loaded by the output wheel 40.

[0074] The second guide wheel 36 allows for the implementation of the end turning section 22c of the heated tunnel 22 between the two longitudinal sections 22a and 22b.

[0075] Reference Figure 1 This causes at least one of the two guide wheels 34 and 36 to rotate counterclockwise. As a result, the preform 12 moves longitudinally forward along the heating path, passing through the first section 22a of the tunnel, then into the end turning section 22c, and finally longitudinally backward through the second section 22b of the tunnel.

[0076] according to Figure 3In a non-limiting embodiment of the heating station 10 shown, the outer wall 26 of the heating tunnel 22 is formed by the inner surfaces of a plurality of heating modules 42. Each heating module 42 includes a radiant heating device that radiates heating radiation 46 generally laterally toward the interior of the heating tunnel 22. Here, as a non-limiting example, this relates to lamps 44 that emit in the infrared spectrum.

[0077] The inner wall 24 of the heated tunnel 22 is formed by one face of a cooling block 48. The cooling block 48 is arranged laterally between the two longitudinal sections 22a and 22b of the tunnel. Figure 3 As schematically shown, the cooling block 48 includes a ventilation device, such as a fan 50, which blows a forced airflow that is laterally guided through a grid formed in the inner wall 24 into the interior of the tunnel 22.

[0078] Tunnel 22 is used to receive the body 18 of the preform 12 with the neck 16 tilted downwards. Their axis "A" is vertical so as to allow them to be heated to the temperature required for subsequent operations of final container forming.

[0079] In a variant not shown, the preform travels with the neck facing upwards.

[0080] Tunnel 22 extends vertically downwards to a channel 52 for the passage of the neck 16 of the preform 12. As described above, the neck 16 of the preform 12 should be warm, i.e., it should be kept at a temperature below the glass transition temperature of the materials constituting them.

[0081] When the heating module 42 includes a radiant heating device, radiation is emitted in all directions, including toward the neck 16 of the preform 12. To limit the flow of heating radiation from the tunnel 22 to the channel 52 or to limit the convection of hot air, at least one pair of heat protection frames 54 for the neck 16 of the preform 12 are vertically inserted between the tunnel 22 receiving the preform body and the channel 52 receiving the neck 16 of the preform. Thus, the protection frames 54 vertically define the tunnel 22. The protection frames 54 extend parallel in the longitudinal direction. Each longitudinal segment 22a, 22b is provided with a pair of protection frames 54.

[0082] The upper surface of each protective frame 54 facing the tunnel 22 advantageously forms a reflective surface that can reflect heating radiation toward the body 18 of the preform 12. To prevent heat buildup in the protective frame 54, each protective frame 54 is advantageously equipped with a cooling device 55, such as a cooling loop in which a heat transfer fluid circulates.

[0083] Furthermore, to prevent heat from the channel 56 from heating the air contained in the channel 52, a second ventilation device 76 can be arranged to blow a forced airflow laterally into the channel 52 to exhaust hot air from the channel, such as... Figure 2 As shown,

[0084] According to an embodiment variant of the heating station (not shown), the heating device is formed by components for emitting heating laser radiation. The main body of the preform is thus locally heated, and the heat is not radiated in all directions. In this case, the ventilation system does not need to be as powerful as in a configuration heated by a radiant heating device. Furthermore, the preform preferably travels with its neck upwards, because the tunnel is not exposed to significant radiation, and therefore the neck is unlikely to be heated by convection as in the first embodiment. In this embodiment variant, the heating station is also equipped with at least one pair of platforms, but here it refers to guide platforms for guiding the preform. The platforms therefore do not have a heat-insulating function as in the case of heat-protected platforms. Therefore, this guide platform is similar to Figure 3 The test stands shown do not have cooling devices.

[0085] In the following text, the term "rampe 54" will be used indiscriminately to indicate... Figure 3 The protective stand of the illustrated embodiment and the guide stand of the embodiment variant not shown are independently applicable to the illustrated embodiment and the embodiment variant not shown.

[0086] The heating station 10 typically includes two pairs of heating stations 54, each pair located in the associated longitudinal sections 22a and 22b of the tunnel 22, while the turning section 22c is not equipped with a heating station.

[0087] A pair of stands 54 are arranged on both sides of the heating path of the preform 12 in the same longitudinal and transverse plane. For this purpose, the stands 54 are laterally spaced to leave longitudinal channels 56 for the travel of the preform 12.

[0088] A pair of stands 54 are arranged in the neck section 21, that is, when the preform 12 moves downward with the neck 16, the stands are arranged above the ring 20 of the preform 12, or when the preform 12 moves upward with the neck 16, the stands are arranged below the ring 20.

[0089] In one production method at a heating station, the transverse width of the channel 56 is equal to the sum of the neck diameter "D1" of the preform 12 and the transverse clearance "j", such as... Figure 3 As shown. The lateral clearance "j" is distributed on both sides of the preform in two approximately equal portions "j / 2" to allow the preform to travel between the stands 54 without contacting them. Therefore, the clearance "j" is equal to the sum of the two portions "j / 2 + j / 2". The width of the channel 56 is here smaller than the outer diameter of the ring 20 of the preform 12.

[0090] To accommodate various preform sizes 12, the width of the channel 56 is adapted to fit different preform sizes, at least one of the pairs of stands 54 is mounted to be laterally movable relative to the heated tunnel 22. This allows for variations in the width of the channel 56. Figure 3 In the example shown, the two stands 54 of the pair are mounted so that they can move laterally relative to the heated tunnel 22.

[0091] Furthermore, the lateral movement of the test bench 54 is controlled by a motorized device 58A for lateral movement in order to automatically adjust the width of the channel 56. The motorized device 58A for lateral movement can be automatically controlled by the electronic control unit 60.

[0092] In a variant of the invention (not shown), the heating module is also mounted to be laterally movable relative to the path of the preform. The heating module may be fixed to a platform, for example, or moved independently via a mechanism similar to a platform moving mechanism.

[0093] The motorized device 58A for the lateral movement platform 54 includes a plurality of lateral movement mechanisms 59A mounted along the platform 54. Each lateral movement mechanism 59A is formed by a mechanical actuator. Such a lateral movement mechanism 59A includes a nut 63 fixedly mounted on the protective platform 54 and a threaded rod 65A, as shown below. Figure 3 As shown. Rod 65A can be guided to rotate within housing 67A, which is laterally fixed relative to frame 66 of heating station 10. Frame 66 is more specifically fixed relative to the ground it rests on.

[0094] Rod 65A is connected to a rotary drive mechanism that ensures the rotation of the drive rod. The rotary drive mechanism includes a gear 68, which rotates integrally with rod 65A. Gear 68 is associated with a threaded shaft 70. This threaded shaft 70 extends entirely longitudinally along the associated platform 54 by engaging with gear 68 of each lateral movement mechanism 59A associated with the platform 54. Gear 68 is housed within a fixed housing 67A.

[0095] The rotation of the threaded shaft 70 is controlled by a motor 74 located at the end of the shaft, such as... Figure 4 As shown. Depending on the rotation direction of the motor 74, this causes the protective platform 54 to translate laterally in one direction or the other, so that the protective platforms 54 separate or bring them closer together.

[0096] The motor 74 of the motorized device 58A used for lateral movement is automatically controlled by the electronic control unit 60.

[0097] The motors 74 controlling the lateral movement of the same pair of test benches 54 can be operated simultaneously so that the two test benches 54 are simultaneously brought closer or separated from each other by the same distance. Therefore, the test benches 54 are always symmetrical about the same intermediate plane fixed relative to the frame 66, regardless of the width of the channel 56. As the preform travels between the pair of test benches 54, the main axis "A" of the preform 12 lies approximately in this intermediate plane.

[0098] Of course, the motorized device for lateral movement is described herein as a non-limiting example. The invention is applicable to moving devices of various designs, such as pneumatic actuators, hydraulic actuators, linear motors, etc.

[0099] When the specifications of the preform 12 change, more specifically, when the inner diameter D2 of the neck 16 of the next batch of preform 12 is different from the inner diameter of the neck of the previous batch of preform 12, the first type retaining member 30 applicable to the previous batch of preform 12 must be replaced with the second type retaining member 30 applicable to the next batch of preform 12 so that these retaining members match the inner diameter D2 of the next batch of preform 12.

[0100] Therefore, the heating station 10 operates in a regulating mode, during which the conveyor 28 does not convey any preforms 12. In the regulating mode, some functions, such as heating, are not yet fully activated, which is the opposite of the production mode in which all functions, including heating, are activated.

[0101] In this change, all the retaining members 30 of the first type are removed from their movable supports 32, and then the retaining members 30 of the second type are installed in the appropriate positions on each movable support 32.

[0102] This invention provides a method for inspecting retaining member 30 after replacement. This method is intended to be applied to each retaining member 30 suchly replaced. Therefore, it can be initiated after all retaining members 30 have been replaced or during the replacement process. This method is applied before the heating station is put into production mode. This avoids any risk of failure associated with errors during retaining member 30 replacement.

[0103] To apply this method, the manufacturing equipment is equipped with an image capture device 78, such as... Figure 1 As shown. The image capturing device 78 is, for example, a camera or digital sensor camera capable of capturing digital images. The image capturing device 78 is arranged to capture images of each holding member 30 along a closed loop.

[0104] More precisely, the image capturing device 78 is arranged here in the heating station 10 to capture images of each holding member 30 along the heating path. More specifically, the image capturing device 78 is arranged to capture images of the holding member 30 when the associated movable support 32 enters the defined acquisition area "Z1" of the heating path.

[0105] More precisely, the image capturing device 78 is arranged here to capture the profile of each holding member 30 in a radial direction relative to axis "A".

[0106] Here, the acquisition area "Z1" is located in the end bend section 22c. The image capture device 78 is located outside the end bend section 22c. This arrangement is particularly advantageous because this area of ​​the heating station 10 typically has sufficient free space to receive the image capture device 78. Furthermore, the tunnel 22 does not have a heating device in its bend section 22c. This prevents the image capture device 78 from being damaged by excessively high temperatures.

[0107] In a variant, the acquisition area can be located at any other point in the closed loop within the area where the image capture device can be placed.

[0108] Each step of the positioning method is automatically executed by the electronic control unit 60.

[0109] In the first step "E1" of actuating passage, the movable support 32 is moved along its closed loop so that each movable support 32 is successively brought into the collection area "Z1". Their holding members 30 cycle empty, that is, they cycle without the preform.

[0110] The first step, “E1,” can be initiated after all retaining components have been replaced. Here, the movable support 32 can move continuously or intermittently throughout the inspection process.

[0111] The first step "E1" can also be initiated before replacing all retaining members 30. Here, it is necessary to temporarily stop the movement of the movable support 32 so that the replacement of the retaining members 30 can be allowed when the movable support 32 enters the replacement zone "Z2".

[0112] The method also includes a second step “E2”, which involves acquiring an image of each individual retaining member 30 as each active support 32 passes through the acquisition area “Z1” using an image capture device 78.

[0113] When each active support 32 that has undergone a replacement operation in the replacement zone "Z2" arrives at the acquisition zone "Z1", the second step "E2" is initiated.

[0114] In the variant, when all retaining components 30 have been replaced in advance, the second step "E2" begins simultaneously with the first step "E1" that initiates the movement.

[0115] The method includes a third step “E3”, which involves automatically checking the presence of the holding member 30 in each image by means of an electronic control unit 60 through computer processing of each image captured in the acquisition step “E2”.

[0116] After capturing each image in the second acquisition step "E2", the third step "E3" can be performed directly on each image.

[0117] In the variant, after the second acquisition step "E2" is completed when each active support 32 takes an image through the acquisition area "Z1", the third step "E3" is executed.

[0118] The method includes a fourth warning step "E4", which is initiated when at least one retaining member 30 is detected not to be present on the movable support 32 during inspection step "E3", and the electronic control unit 60 issues a warning signal. This signal allows the operator to correct this omission by equipping the relevant movable support 32 with the retaining member 30.

[0119] Advantageously, the electronic control unit 60 allows the location of the movable support 32, excluding the retaining member 30, based on the position of the corresponding image in the sequence of image capture time.

[0120] Repeat each of steps E1 to E4 of this method until the presence of the retaining member 30 is checked on each active support 32.

[0121] Furthermore, during changes to the preform specifications, the test bench 54 needs to be precisely positioned to ensure that the channel 56 has sufficient width to allow the preform 12 to travel smoothly. However, the channel 56 should be narrow enough to minimize heat transfer between the tunnel 22 and the channel 52 via radiation or convection if the test bench 54 is a thermally protected test bench, or to allow for effective guidance of the preform if the test bench 54 is a guiding test bench.

[0122] The present invention optionally proposes to automatically position a pair of stands 54 when inspecting the holding member 30.

[0123] Reference Figure 5 The inspection method includes a fifth step, “E5”, which involves automatically determining the outer diameter “D3” of the retaining member 30. This fifth step is initiated after the acquisition step, “E2”.

[0124] In the fifth step, the outer diameter "D3" of the retaining member 30 is determined by computer processing of the image of the retaining member 30 obtained in the acquisition step "E2" using the electronic control unit 60.

[0125] According to the first embodiment of the fifth determination step "E5", the outer diameter "D3" of the retaining member 30 is determined by identifying the visual markers carried by each retaining member 30.

[0126] For example, this involves a barcode or matrix code, such as a QR code, applied to each retaining member 30. This code may appear on each image captured during acquisition step "E1". Therefore, the electronic control unit 60 is able to identify and read the information contained in the code. The code itself may directly contain the outer diameter of the retaining member 30.

[0127] In a variant, the code contains a reference number for the retaining member 30. The electronic control unit 60 includes a pre-recorded database, allowing each reference number to correspond to an outer diameter "D3" of the retaining member 30.

[0128] According to the second embodiment of the fifth determination step "E5", the outer diameter "D3" of the retaining member 30 is determined by shape recognition on the image of the retaining member 30 captured during the acquisition step "E2".

[0129] For this purpose, the image capturing device 78 is advantageously positioned at a predetermined distance "C" from the retaining member 30, with the movable support 32 of the retaining member 30 located in the acquisition area "Z1" during image acquisition. This allows the proportion of the retaining member 30 appearing in the image to be known without referring to visual markers. The image capturing device 78 is designed and positioned to capture a digital image of the retaining member 30 with a sufficiently high resolution to perform an operation capable of determining the outer diameter "D3" of the retaining member 30 with an accuracy of less than 1 mm.

[0130] For example, the electronic control unit 60 measures the outer diameter "D3" of the holding member 30 on the image. Then, the electronic control unit 60 multiplies the dimension measured on the image by a predetermined scaling factor "K". The scaling factor "K" is calculated in particular based on various known parameters, such as its distance from the image capturing device 78 and the characteristics of the optics equipped with the device.

[0131] The proportionality coefficient "K" can also be defined experimentally during the pre-calibration operation.

[0132] According to a variation of the fifth determination step "E5", the outline of the retaining member 30 presented on the image (referred to as the "detected outline") is compared with the outline of the retaining member (referred to as the "type outline") pre-stored in the electronic control unit 60. In fact, the number of retaining member 30 specifications that can be equipped on the heating station 10 is usually limited. Therefore, the type outline for each of these retaining member 30 specifications can be exhaustively stored in the electronic control unit 60.

[0133] Each stored type profile is associated with an outer diameter “D3” stored in the database of the electronic control unit 60.

[0134] When the specific shape and size of the detected contour roughly correspond to the shape and size of a similar type of contour stored in the database, the electronic control unit 60 is thus able to automatically identify the type contour from the stored type contours through shape recognition. Then, the electronic control unit 60 is able to find the corresponding outer diameter "D3" in the database.

[0135] The method further includes a sixth step, “E6,” which involves automatically adjusting the width of the channel 56 by moving at least one movable platform 54 according to the lower neck diameter “D1” determined in the fifth step, “E5,” when determining the outer diameter “D3,” so that the width of the channel 56 is adjusted to be equal to the lower neck diameter “D1” plus the width of a determined lateral clearance “j.” The lower neck diameter “D1” is determined by adding a predetermined dimension to the outer diameter “D3” of the retaining member 30, wherein the predetermined dimension corresponds to the nominal thickness of the preform wall minus an additional thickness “s.”

[0136] Here, the two platforms 54 of the control pair move simultaneously. For this purpose, the electronic control unit 60 controls the motorized device 58A for lateral movement. The sixth step "E6" for adjusting the width intervenes sequentially after the second step "E2" for determining the lower diameter "D1".

[0137] Advantageously, the method further includes a seventh alarm step “E7”, which is initiated for each retaining member 30 at the end of the detection step “E5”. At this alarm step “E7”, it is confirmed that all retaining members 30 mounted on the movable support 32 have the same outer diameter “D3” or that each retaining member 30 has an outer diameter “D3” that conforms to a preset value input in the electronic control unit 60.

[0138] If this is not the case, a warning message is sent to the operator. This step allows for the prevention of one of the retaining components 30 having an outer diameter that is not suitable for the specifications of the preform 12 loaded when production is resumed.

[0139] Therefore, the inspection method allows for quick and automatic verification that the replacement operation of retaining component 30 has been performed without errors.

Claims

1. A method for automatically checking the presence of a holding member (30) for holding a preform (12) made of thermoplastic material in a heating station (10), the heating station (10) being equipped with a conveying device (28) for conveying the preform (12) along a heating tunnel (22), the conveying device (28) comprising: - Multiple active support components (32); - Retaining member (30) for individually retaining preform (12) through neck (16) of preform, each retaining member (30) is supported by a movable support (32) and the retaining member (30) is detachably fixed to its respective movable support (32); The method is characterized by comprising: - The step (E1) of moving the movable support (32) to successively bring the movable support into the collection area (Z1); - Acquisition step (E2) using image capture device (78) to acquire an image of each holding member (30) for individual holding as each active support (32) passes through acquisition area (Z1); - An inspection step (E3) is performed by using an electronic control unit (60) to automatically check the presence of the holding member (30) in each image by computer processing each image captured in the acquisition step (E2).

2. The method according to claim 1, characterized in that, When at least one retaining member (30) is detected not to be present on the movable support (32) during the inspection step (E3), an alarm signal is issued by the electronic control unit (60).

3. The method according to claim 1, characterized in that, The retaining member (30) is formed by a mandrel for insertion into the neck (16) of the preform (12), and each retaining member (30) is to be replaced when the preform (12) is changed so that the outer diameter (D3) of the retaining member (30) matches the inner diameter (D2) of the neck (16) of the preform (12).

4. The method according to claim 1, characterized in that, The method is initiated after the replacement of the retaining member (30) begins and before the heating station is put into operation.

5. The method according to claim 1, characterized in that, The heating station (10) includes: - At least one pair of longitudinal supports (54) defining channels (56) for the travel of the preform (12), at least one longitudinal support (54) being laterally movable to change the width of the channels (56); - At least one motorizing device (58A) for laterally moving the at least one active longitudinal platform (54) to adjust the width of the channel (56), the motorizing device (58A) being automatically controlled by an electronic control unit (60).

6. The method according to claim 5, characterized in that, The retaining member (30) is formed of a mandrel for insertion into the neck (16) of the preform (12), each retaining member (30) being replaced when the specifications of the preform (12) are changed, so that the outer diameter (D3) of the retaining member (30) matches the inner diameter (D2) of the neck (16) of the preform (12); and the method includes: - The determination step (E5) of the outer diameter (D3) of the retaining member (30) is automatically determined by computer processing at least one of the images captured in the acquisition step (E2); - Step (E6) to automatically adjust the width of the channel (56) by moving the at least one longitudinal platform (54) of the activity according to the outer diameter (D3) determined in step (E5).

7. The method according to claim 6, characterized in that, During the acquisition step (E2), the image capture device (78) captures the profile of the holding member.

8. The method according to claim 7, characterized in that, The image capturing device (78) is positioned at a predetermined distance (C) from the holding member during image capture operation.

9. The method according to claim 6, characterized in that, The type of retaining member is determined by identifying the visual markers carried by each retaining member.

10. The method according to claim 8, characterized in that, In the determination step (E5), the outer diameter (D3) of the retaining member (30) is obtained by multiplying the width of the retaining member (30) measured on the image by a predetermined scaling factor (K).

11. The method according to claim 8, characterized in that, In the determination step (E5), the outline of the retaining member (30) presented on the image is compared with the outline of the retaining member (30) stored by the electronic control unit (60), each stored outline being associated with the outer diameter (D3) stored by the electronic control unit (60).

Images