SYSTEM FOR TRANSPORTING OBJECTS MADE OF THERMOPLASTIC MATERIAL WITH A HOLLOW BODY AND A NECK

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a conveying system for thermoplastic objects comprising a hollow body with a neck, such as preforms or containers. STATE OF THE ART

[0002] The invention relates more particularly to a conveying system for thermoplastic objects comprising a hollow body with a neck, such as preforms or containers, said system comprising at least: a first wheel equipped with transfer arms, each fitted with a gripper for grasping an object and driven around a first axis of rotation by first drive means, and a second wheel equipped with transfer arms, each fitted with a gripper for grasping an object and driven around a second axis of rotation by second drive means, said second wheel being driven in a direction opposite to that of the first wheel, in which the first drive means and the second drive means are each motorized and are electronically synchronized to operate, at a given transfer point, a gripper-to-gripper type transfer of an object from the first wheel to the second wheel located downstream.

[0003] We know of prior art examples of such a conveying system for objects made of thermoplastic material which is notably used in a facility for manufacturing containers from preforms.

[0004] In a thermoplastic container manufacturing facility, particularly for bottles, such a conveying system is used to ensure successive transfer of preforms and then of containers, respectively between the different machines of the facility.

[0005] As a non-limiting example, document FR-2.972.671 describes a manufacturing facility for thermoplastic containers.

[0006] As illustrated by the figure 1 According to this document, such a manufacturing installation mainly comprises an oven for thermally conditioning preforms which are then transferred to a molding machine (or "blower") to be transformed into containers by blowing (or stretch-blowing) into a mold at one of the stations of said machine.

[0007] The resulting containers are then transferred downstream, for example to a filling and capping machine and then to a labeling machine.

[0008] Alternatively, the arrangement of the filling (and capping) machine and the labeling machine can be reversed so that the containers are labeled before being filled and then sealed.

[0009] In a container manufacturing facility, the conveying system ensures the transfer of preforms from the oven outlet and then the containers, all following a path that marks the different stages of the manufacturing process.

[0010] To do this, the conveying system includes a succession of transfer devices, also called "wheels", some of which at least include a plurality of transfer arms equipped at their free end with a gripping clamp capable of gripping at the neck level of at least one preform or container.

[0011] Document FR-2.972.671 further describes a "clamp-to-clamp" type transfer of a preform, respectively between a clamp of an arm of a first transfer device and another clamp of an arm of a second transfer device arranged downstream of the first.

[0012] In document FR-2.972.671, the part of the conveying system described more specifically ensures a transfer of preforms between the oven outlet and the container molding machine.

[0013] Figures 5 to 8 illustrate the clamp-to-clamp transfer of a preform and in particular the respective position of the jaws of the first clamp and those of the second clamp which each cooperate with parts of the neck of the preform offset vertically so as to avoid any interference between them.

[0014] The clamp-to-clamp transfer of the preform takes place at a transfer "point" where the wheel forming the first transfer device and the wheel forming the second transfer device are tangential.

[0015] To ensure such a transfer from one gripper to another, it is essential to be able to guarantee perfect synchronization between the transfer wheels and more generally to ensure this synchronization over the entire conveying path through the installation.

[0016] According to a known solution, synchronization is ensured mechanically by means of at least one belt linking, for example, a transfer device driven in rotation by a motor to another transfer device whose synchronous rotational drive is ensured by the belt.

[0017] Such a solution does not give complete satisfaction due in particular to the maintenance interventions required and therefore other solutions have been sought in order to eliminate the transmission belts which also ensure a synchronous rotation drive of the transfer wheels of the system.

[0018] Another known solution addresses the aforementioned drawbacks by eliminating all mechanical links. In this alternative solution, synchronization is achieved electronically, at least between the transfer wheels. Each wheel is equipped with a rotational drive system, such as asynchronous motors, particularly brushless motors.

[0019] The motors are generally controlled by a control unit that receives information from a set of synchronization sensors, encoders, etc., in order to automatically synchronize the entire container manufacturing installation, the conveyor system's transfer wheels, as well as the container molding (or "blow molding"), filling and capping, labeling, and other machines. In other words, such a system has a synchronization configuration between the first and second drive means, each being motorized and controlled by a control unit designed to electronically bring the system to and / or maintain it in a synchronized configuration to operate, at a given transfer point, a gripper-to-gripper transfer of an object from the first wheel to the second wheel located downstream.

[0020] However, such electronic synchronization can malfunction, particularly in the event of power supply problems, typically outages or power surges, which are sometimes frequent in certain countries. In other words, such a system can exhibit a desynchronized configuration.

[0021] To prevent such power supply problems with the motors, capacitors are used. The use of capacitors makes it possible to maintain a motor's power supply for a specific duration, particularly to allow for a shutdown of the conveyor system's drive wheels and, more generally, of the manufacturing installation, if necessary.

[0022] However, the use of such capacitors has disadvantages, including their particularly large size and cost.

[0023] Although considered, it is not possible to reduce their number except by also reducing the duration during which the capacitors can compensate for a power supply failure.

[0024] If the power supplied by the capacitors is insufficient to allow a safe stop of the drive of the transfer wheels of the conveyor system, there is a risk of desynchronization of the drive of the transfer wheels before such a stop.

[0025] However, such a risk of desynchronization is likely to cause damage to the clamps of the transfer arms.

[0026] In the absence of synchronization, there is indeed a significant risk of damage to the gripping clamps at the point of transfer of a preform or container, and in so doing, of deterioration or even destruction (breakage) of at least one of the clamps.

[0027] Damage to the grippers is particularly likely to occur in the event of a collision between the neck of an object (preform or container) conveyed by a gripper of one of the transfer arms of a first wheel and another gripper of one of the transfer arms of a second wheel, located downstream and out of sync with the first wheel.

[0028] Due to the high production rates, the drive speeds of the transfer wheels are also high, and in addition, the neck usually has a significant amount of thermoplastic material, resulting in a similarly high resistance.

[0029] Furthermore, document JP2008044768 describes an object conveying system with a device that allows containers to either pass along their conveying path or reject them. Document JP2015 067333 discloses the features of the preamble to claim 1. Document EP1970329 describes a bottle conveying system between two wheels, each equipped with clamps. One of the wheels has clamps that can be opened, each clamp being equipped with a retraction mechanism that can be opened. Document JP2008 044768 describes a bottle dryer equipped with an overheated bottle discharge wheel.

[0030] It is worth noting that the neck of a preform or container (such as a bottle) made of thermoplastic material is the same, the neck having its final shape after the injection molding of the preform.

[0031] The aim of the invention is in particular to remedy at least in part the aforementioned disadvantages of the solutions of the state of the art and to propose a new solution for a conveying system for objects made of thermoplastic material having a neck, said system remaining advantageously simple, reliable in use and generally economical. BRIEF SUMMARY OF THE INVENTION

[0032] To this end, the invention proposes a system for conveying thermoplastic objects of the type described above, characterized in that the system comprises at least one ejection device which, arranged upstream of the transfer point, is selectively activated in the event of desynchronization between said first and second drive means to eject the objects conveyed by the first wheel so as to prevent any damage to the grippers in the vicinity of the transfer point. The ejection device is activated in the event of desynchronization between said first and second drive means. The ejection device comprises ejection means which are arranged, upstream of the transfer point, to come into contact with at least one object conveyed by the first wheel in order to cause its ejection from the gripper of the transfer arm of the first wheel.

[0033] The synchronization configuration means that at a succession of periodic instants, a gripper from the first wheel and a gripper from the second wheel arrive simultaneously at the transfer point T in such a way as to cooperate to allow a gripper-to-gripper transfer of an object.

[0034] Advantageously, the ejection device is controlled selectively only in the event of desynchronization between said first drive means of the first transfer wheel and the second drive means of the second transfer wheel located downstream and in relation to the first wheel at the point of transfer of the objects.

[0035] Thanks to the invention, the risk of damage to the grippers at the transfer point is eliminated since, in the event of desynchronization, the ejection device intervenes upstream to empty the grippers of the transfer arms of the first wheel by ejecting the conveyed objects.

[0036] Thus, the neck of an object conveyed by a first gripper is no longer likely to hit a second gripper when the said grippers cross in the vicinity of the transfer point.

[0037] The invention can in particular make it possible to substantially reduce the use of capacitors in a conveyor system to prevent the consequences of power supply problems such as outages.

[0038] Advantageously, the invention allows at the very least the size of the capacitors to be reduced compared to the prior art and in so doing to obtain a significant space saving which makes it possible to reduce the overall footprint of a container manufacturing installation comprising a conveying system equipped with at least one ejection device. According to other characteristics of the invention:

[0039] The control unit is connected to means for determining in real time the angular position of the first and second wheels relative to a machine reference. The control unit is programmed to detect a desynchronized configuration and either return the system to the synchronized configuration or authorize the ejection device. The ejection device comprises ejection means that are movably mounted between at least one passive position in which said ejection means do not interfere with the conveying of objects by the first transfer wheel, and an active ejection position in which said ejection means act to cause the ejection of objects conveyed by the first transfer wheel; the ejection device comprises means for actuating the ejection means to move them into the passive position and / or into the active ejection position; the actuating means are controlled to maintain the ejection means in the passive position and such that the ejection means are automatically returned to the active ejection position; the ejection means comprise at least one ejection member that is arranged vertically to come into contact with said at least one object in the vicinity of the neck;said at least one ejection member is formed by a blade; the ejection device includes ejection means capable of opening at least one gripper to eject the conveyed object from the gripper of the transfer arm of the first wheel; the ejection means include at least one ejection member capable of acting on at least one gripper control mechanism to open it; said at least one ejection member is formed by a cam; said ejection device is a first ejection device, the system including at least one second ejection device, arranged upstream of the first ejection device; the system includes at least one systematic ejection device, arranged downstream of the transfer point to systematically eject any object conveyed by the first wheel beyond the transfer point.

[0040] According to another aspect of the invention, the method for conveying thermoplastic objects comprising a hollow body with a neck uses a first conveyor equipped with a plurality of first individual grasping means for the objects to be conveyed along a first conveying path, and a second conveyor equipped with a plurality of second individual grasping means for the objects to be conveyed along a second conveying path tangent to the first conveying path at a transfer point (T). The method includes a synchronized operating step in which each of the first grasping means arriving at the transfer point (T) cooperates with a complementary second transfer means to transfer an object from the first grasping means to the second grasping means.According to the invention, the method includes an asynchronous operating step, in which the objects are ejected from the first gripping means before they reach the transfer point (T). BRIEF DESCRIPTION OF THE FIGURES

[0041] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: there figure 1 is a schematic top view representing an example of an implementation of a thermoplastic container manufacturing installation and illustrating a conveying system according to the invention equipping such a manufacturing installation; the figure 2 is a top view that represents part of the conveyor system according to the figure 1and which illustrates more particularly a first transfer wheel and a second transfer wheel, said first transfer wheel comprising, according to an embodiment of the invention, three ejection devices, at least one of which is selectively controlled to eject the conveyed objects in the event of desynchronization between the rotational drive means of said transfer wheels; the figures 3 And 4 are respectively a perspective view and a side view which represent the transfer wheels according to the figure 2 and which illustrate the arrangement of said ejection device according to the embodiment in which the first transfer wheel also includes two other ejection devices. DETAILED DESCRIPTION OF THE FIGURES

[0042] In the remainder of the description, the longitudinal, vertical and transverse orientations will be adopted without limitation with reference to the trihedron (L, V, T) shown in the figures.

[0043] By convention, the longitudinal and transverse orientations are fixed relative to the transfer wheel of the conveying system so that the position of the transfer arms containing the grippers has no effect on said orientations.

[0044] The terms "front" and "rear" will also be used, without limitation, in reference to longitudinal orientation, as well as "upper" and "lower" or "top" and "bottom" in reference to vertical orientation, and finally "left" and "right" in reference to transverse orientation.

[0045] The terms "upstream" or "downstream" are used respectively in relation to the direction of flow of objects, preforms or containers, conveyed by the wheels of the system through the installation.

[0046] It has been represented on the figure 1an example of the implementation of a 100% thermoplastic container manufacturing plant.

[0047] The manufacture of containers such as bottles, flasks, jars, etc. is carried out from preforms obtained in particular by injection molding.

[0048] Such a preform has a neck which has its final shape, that is to say that of the neck of the final container obtained at the end of the manufacturing process.

[0049] As a non-limiting example, the thermoplastic material used is polyethylene terephthalate (PET).

[0050] Installation 100 mainly comprises an oven (not shown), a molding machine 110, a labeling machine 120 and a filling machine 130.

[0051] The manufacture of the containers is achieved in a manner similar to that described previously with reference to document FR-2.972.671, to which further details may be referred.

[0052] The oven is intended to thermally condition the hollow body of the preforms which are then introduced into molds of the molding machine 110 in which their transformation by blowing or by stretch-blowing into containers is carried out.

[0053] In the example embodiment, the containers obtained are transferred to the labeling machine 120 and then to the filling machine 130.

[0054] Alternatively, the labeling machine 120 is arranged downstream of the container filling machine 130 as illustrated by the figure 1 from document FR-2.972.671.

[0055] As explained previously in the preamble, such an installation 100 includes a system 10 for conveying objects made up of preforms and then containers made from said preforms.

[0056] Indeed, preforms and containers are identical objects to be conveyed because they have the same neck. The neck is generally fitted with a collar that extends radially outwards at the junction of the neck and the hollow body.

[0057] In the rest of the description, the term "object" therefore refers indifferently to a preform or a container.

[0058] During their conveyance by such a system 10 through the installation 100, the object is either supported by means of such a collar, or grasped by the neck by a clamp, for example at the level of an annular groove located vertically above the collar.

[0059] To ensure the conveying of objects, preforms or containers, the conveying system 10 comprises a plurality of conveying devices which are arranged to successively transport said objects through the manufacturing installation 100.

[0060] The conveying system 10 includes rotary-type conveying devices, schematically represented for this reason on the figure 1 by circles.

[0061] In the example, the conveying devices of system 10 are suitable for conveying the preforms and then the containers forming said objects equipped with a neck and comprising a hollow body.

[0062] Two main types of conveying devices are distinguished depending on whether the object is supported via its radial collar or whether a grip is made at the neck level.

[0063] In the embodiment example and in accordance with the second solution mentioned above, each device of the conveying system 10 is driven in rotation by a motor which is electronically controlled synchronously.

[0064] Whatever their type, the devices are driven in rotation around a vertical axis by motorized drive means, which is why these conveying devices are also called "wheels".

[0065] The first type of conveying device includes at least one circumferentially movable platform provided with a plurality of notches having, for example, a "U" shape radially open outwards.

[0066] Objects are inserted radially into the notches and supported by their flanges resting on the notch's perimeter. Such a device is sometimes called a "notched wheel" for this reason.

[0067] The second type of conveying device includes at least one movable wheel equipped with a plurality of transfer arms, each of which is fitted at its free end with a clamp having two jaws.

[0068] There are different types of grippers, depending in particular on the part of the object with which the gripper jaws interact. Grippers are thus distinguished according to whether the jaws are positioned below the radial flange of the object's neck or whether the jaws provide a grip with a clamping force on the neck above the flange.

[0069] The jaws are, for example, attached to one free end of the levers of a clamp. The jaws are mounted to move between at least one open position and one closed position.

[0070] The open position corresponds to a position in which the object can be inserted into or extracted from an opening delimited by the jaws in the closed position.

[0071] The jaws of the pliers are usually automatically returned to the closed position by means of return, such as a spring.

[0072] Depending on their design, a further distinction can be made between clamps in which the object is forced into or out of the jaws, compared to other clamps in which at least the opening is controlled by means of a mechanism, for example a cam and roller type actuation mechanism.

[0073] We know from earlier art many examples of the making of such clamps intended to equip conveying devices which will therefore not be described in more detail.

[0074] As a non-limiting example, reference may be made to document FR-2.915.475 which describes in particular a control mechanism for opening and closing the levers of a gripping clamp for a preform in a linear type container manufacturing installation.

[0075] Reference can also be made to other documents FR-2.479.077 (figures 10 and 11) or FR-2.774.666 which illustrate examples of the making of clamps.

[0076] It has been represented on the figures 2 to 4 only part of the conveyor system 10 according to the figure 1 .

[0077] The conveying system 10 includes at least a first conveying device 12 and a second object conveying device 14, respectively designated hereinafter as first wheel 12 and second wheel 14.

[0078] As illustrated on the figure 1 , the first wheel 12 is arranged downstream of the molding machine 110, here directly at the outlet, and the second wheel 14 is located immediately downstream of the first wheel 12.

[0079] The objects conveyed by the first wheel 12 and the second wheel 14 are therefore made up of containers, for example bottles.

[0080] The first wheel 12 is provided with a plurality of transfer arms 16 which are distributed circumferentially in a regular manner on a rotating plate 18.

[0081] It has been represented on the figure 2 only two of these transfer arms 16 in the angular sector including in particular a transfer point which is referenced "T" and corresponds to the point at which the transfer of containers from the first wheel 12 to the second wheel 14 takes place.

[0082] Each transfer arm 16 is equipped with a gripper 20 for grasping at least one object, here a container.

[0083] According to a non-limiting embodiment, the gripper 20 takes a container from a mold (not shown) along a carousel of the blow molding machine 110 and brings this container into an arm of the second wheel 14, as illustrated in figure 1 .

[0084] Advantageously, but not necessarily, the arm 16 pivots along a first cam track visible in figure 3 and the clamp 20 is movable in translation along the arm 16 following an outer edge of the cam visible in figure 3. Thus two successive containers separated by a first step along the blowing carousel, are brought along the second wheel 14 with a second step smaller than the first step.

[0085] However, the first wheel 12 and the second wheel 14 can be located anywhere along an object conveying path, particularly when this object conveying is done continuously and during which each object is held individually.

[0086] The clamp 20 has two jaws 22 which are mounted to move between an open position and a closed position.

[0087] Preferably, the clamp 20 includes elastic return means for the jaws to the closed position and a mechanism 24 for selectively controlling the clamp 20 in the open position, against said elastic return means.

[0088] The opening control mechanism 24 for the clamp 20 includes at least one roller 26 which is intended to cooperate with a cam 28.

[0089] The first wheel 12 is driven around a first axis A1 of rotation by first means 30 of drive comprising at least one motor (not shown).

[0090] The cam 28 is for example attached to a support plate 32 which is fixed relative to the mobile plate 18 comprising the transfer arms 16 and driven in rotation by the first drive means 30.

[0091] The second wheel 14 is of similar design to the first wheel 12.

[0092] The second wheel 14 is equipped with a plurality of transfer arms 34, each equipped with a clamp 36 for gripping at least one container, here forming the said object conveyed in this part of the installation by the conveying system 10.

[0093] As before, only part of the transfer arms 34 has been shown, more precisely two arms 34, one of which is in a clamp-to-clamp transfer position with a clamp 20 transferring the first wheel 12.

[0094] The second wheel 14 has a movable platform 38 to which the transfer arms 34 are linked in motion.

[0095] The second wheel 14 is driven by second means 40 of drive around a second axis A2 of rotation, the second wheel 14 being driven in a direction of rotation opposite to that of the first wheel 12.

[0096] The second wheel 14 has a fixed support plate 42 relative to the rotating plate 38.

[0097] The first 30 drive means and the second 40 drive means respectively motorized are electronically synchronized to operate, at the transfer point T, a clamp-to-clamp type transfer of the containers from the first wheel 12 to the second wheel 14 located downstream.

[0098] The conveying system 10 includes at least one ejection device 44 which is arranged upstream of the transfer point T.

[0099] Preferably, the ejection device 44 is carried by the first wheel 12, for example fixed to the plate 18.

[0100] The ejection device 44 is selectively controlled in the event of desynchronization between the first drive means 30 and the second drive means 40, in particular following a problem with the electrical supply.

[0101] The ejection device 44 has the function of ejecting, in the event of desynchronization, the containers conveyed by the first transfer wheel 12 in order to avoid any damage to the clamps 20 and / or the clamps 36 in the vicinity of the transfer point T.

[0102] Damage to the clamps is likely to occur in particular in the event of a collision between the neck of a container conveyed by a clamp 20 of one of the transfer arms 16 of the first wheel 12 and a clamp 36 of one of the transfer arms 34 of the second wheel 14, out of sync with the first wheel 12.

[0103] The ejection device 44 is selectively controlled between a passive state occupied when the first drive means 30 and the second drive means 40 are synchronized and an active ejection state occupied only when the first drive means 30 and the second drive means 40 are desynchronized.

[0104] According to the embodiment illustrated by the figures 2 to 4 , the ejection device 44 includes ejection means 46 which are mounted movable between at least one passive position and one active ejection position corresponding to said states.

[0105] The passive position corresponds to a position in which the said ejection means 46 do not interfere with the conveying of the containers by the first transfer wheel 12.

[0106] The active ejection position corresponds to a position in which the said ejection means 46 intervene to cause the ejection of the containers conveyed by the first transfer wheel 12.

[0107] The ejection device 44 includes means 48 for actuating the ejection means 46 to move them into at least one of said passive and active ejection positions.

[0108] Preferably, the actuation means 48 are controlled to maintain the ejection means 46 in a passive position, which are automatically returned to the active ejection position.

[0109] Advantageously, the means 48 for actuation of the ejection device 44 consist of at least one pneumatic cylinder.

[0110] Compared to other electrically operated means of actuation, the operation of a pneumatic cylinder will be less sensitive to the problem of electrical power supply.

[0111] The pneumatic cylinder is for example associated with a distributor in order to be selectively controlled and automatically returned to the active ejection position.

[0112] The actuation means 48 may also include elastic return means such as a spring.

[0113] The ejection device 44 includes ejection means 46 which are arranged upstream of the transfer point T in order to come into contact with the containers conveyed by the first wheel 12 and to then systematically cause the ejection of each container out of the clamp 20 of the transfer arm 16 of the first wheel 12.

[0114] The ejection means 46 include at least one ejection organ 50 which is formed by at least one saber.

[0115] The ejection organ 50 formed by said at least one saber is moved in translation between said passive and active ejection positions by the cylinder forming the actuation means 48.

[0116] Advantageously, the ejection organ 50 is in the active ejection position deployed along the path of the containers and arranged vertically at a determined height to come into contact with the containers in the vicinity of the neck.

[0117] In an unrepresented variant, the ejection means 46 include more than one ejection organ 50, for example at least one other sword offset vertically downwards from the first sword and intended to come into contact with the body of the containers.

[0118] The container conveyed by the clamp 20 consequently strikes the blade forming the ejection organ 50, which will cause it to be ejected from the jaws 22 of the clamp 20, which open under the effect of the impact, thus releasing the container.

[0119] The container ejected by the sword then falls by gravity preferably into collection means, such as bins, arranged to recover ejected containers, in particular to facilitate their subsequent evacuation.

[0120] According to the embodiment illustrated by the figures 2 to 4 , the ejection device 44 advantageously constitutes only one of the ejection devices associated with the first wheel 12.

[0121] The first wheel 12 of the system 10 includes at least one other ejection device 52, called the second, which is arranged upstream of the first ejection device 44.

[0122] The second ejection device 52 has a different function from that of the first ejection device 44, which is intended to intervene in case of desynchronization.

[0123] The second ejection device 52 is controlled to selectively eliminate at least one object, preform or container, according to other determined conditions.

[0124] By way of non-limitation, the second ejection device 52 is notably used in the event of a defect detected on a container requiring its disposal for non-conformity or to take a sample for quality control purposes of the manufactured container.

[0125] Preferably, the second ejection device 52 is identical to the first ejection device 44 and includes at least one ejection saber 54.

[0126] The saber 54 forming the ejection organ is thus moved in translation between the said passive and active positions by means 56 of actuation, such as a jack.

[0127] Advantageously, the system includes at least one systematic ejection device (58), which is arranged downstream of the transfer point T to systematically eject any container conveyed by the first wheel 12.

[0128] The systematic ejection device 58 is intended to prevent any return of a container conveyed by the first wheel 12 downstream of the transfer point T, such as a container not transferred to the second wheel 14 or not ejected by said first ejection device 44.

[0129] In the case where the first wheel is adjacent to the blowing carousel, the systematic ejection device 58 prevents a gripper returning to a mold from still being occupied by a container instead of being available to grasp a newly blown container.

[0130] Such a systematic ejection device 58 may be a third ejection device 58 in addition to the first ejection device 44 and the second ejection device 52. The systematic ejection device 58 may be another ejection device 58 in addition to the ejection device 44.

[0131] The third ejection device 58 includes at least one ejection member 60 which is arranged in a fixed manner relative to the first transfer wheel 12 in order to prevent any return of the container.

[0132] Like the first ejection device 44 and the second ejection device 52, the third ejection device 58 is integral with the first wheel 12 of the conveying system 10.

[0133] Preferably, the ejection organ 60 is a fixed saber which is arranged to systematically eject from the clamp 20 of a transfer arm 16 of the first wheel 12 all containers present.

[0134] Advantageously, and like the saber 50 or 54, the ejection organ 60 of the third ejection device 58 is arranged vertically in height to come into contact with the container in the vicinity of the neck.

[0135] Preferably, the first ejection device 44 is arranged as close as possible to the transfer point T so as to eject upstream all the containers in case of desynchronization.

[0136] However, a container ejected by the first ejection device 44 near the transfer point T where the grippers 20 and 36 intersect could also, depending on its trajectory, cause damage to the grippers.

[0137] This is why the first ejection device 44 is preferentially arranged upstream of the transfer point T.

[0138] However, there is then a possibility that at least one container may become interposed between the first ejection device 44 and the transfer point T, said at least one container continuing to be conveyed by the gripper 20 of a transfer arm 16 which may then cause damage.

[0139] To prevent this risk, a compromise consists of maintaining a reduced use of capacitors, the number of which will be determined in particular according to the angular sector to be covered between the first ejection device 44 and the transfer point T, the number of containers that could be interposed and cause damage to the clamps.

[0140] According to another embodiment (not shown), the ejection device 44 includes ejection means 46 which are capable of causing the opening of at least one gripper 20 to obtain the ejection of the conveyed object, preform or container, out of the gripper 20 of the transfer arm 34 of the first wheel 12.

[0141] The ejection means 46 comprise at least an ejection organ 50 which is formed by a cam.

[0142] The cam forming the ejection organ 50 is capable of acting on the control mechanism 24 of one or more grippers 20 to cause them to open in order to eject the objects, preforms or containers, which will then fall by gravity.

[0143] Like the saber according to the method of realization illustrated by the figures 2 to 4 , the cam is mounted movable between a passive position and an active ejection position and controlled in displacement in at least one of said positions by means of actuation means 48.

[0144] The cam is configured to cause the clamp 20 to open, where appropriate against means for returning the jaws 22 of the clamp to a closed position.

Claims

1. System (10) for conveying objects made of thermoplastic material and comprising a hollow body provided with a neck, said system (10) comprising at least: - a first wheel (12), which is provided with transfer arms (16) each equipped with a gripper (20) for grasping an object and is driven about a first axis (A1) of rotation by first drive means (30), and - a second wheel (14), which is provided with transfer arms (34) each equipped with a gripper (36) for grasping an object and is driven about a second axis (A2) of rotation by second drive means (40), said second wheel (14) being driven in a direction counter to that of the first wheel (12), wherein the system has a configuration of synchronization between said first and second drive means (30, 40), the first drive means (30) and the second drive means (40) each being motor-powered and controlled by a control unit designed to electronically bring the system into and / or keep the system in the synchronization configuration in order to carry out, at a given transfer point (T), a gripper-to-gripper transfer of an object from the first wheel (12) to the second wheel (14) situated downstream, characterized in that the system (10) comprises at least one ejection device (44) that, arranged upstream of the transfer point (T) and comprising ejection means (46), is selectively controlled in the event of desynchronization between said first and second drive means (30, 40) so that said ejection means (46) come into contact with at least one object conveyed by the first wheel (12) in order to cause said object to be ejected from the gripper (20) of the transfer arm (16) of the first wheel (12) so as to avoid any damage to the grippers (20, 36) in the vicinity of the transfer point (T).

2. System according to Claim 1, characterized in that said ejection means (46) are mounted so as to be able to move between at least: - a passive position in which said ejection means (46) do not interfere with the conveying of the objects by the first transfer wheel (12), and - an active ejection position in which said ejection means (46) intervene in order to cause the objects conveyed by the first transfer wheel (12) to be ejected.

3. System according to Claim 2, characterized in that the ejection device (44) comprises means (48) for actuating the ejection means (46) in order to move them into the passive position and / or into the active ejection position.

4. System according to Claim 3, characterized in that the actuating means (48) are controlled to keep the ejection means (46) in the passive position and in that the ejection means (46) are automatically returned to the active ejection position.

5. System according to any one of Claims 1 to 4, characterized in that the ejection means (46) comprise at least one ejection member (50), which is arranged vertically in order to come into contact with said at least one object in the vicinity of the neck.

6. System according to any one of the preceding claims, characterized in that the ejection device (44) comprises additional ejection means (46), which are able to cause at least one gripper (20) to open in order to eject the conveyed object from the gripper (20) of the transfer arm (16) of the first wheel (12).

7. System according to Claim 6, characterized in that the additional ejection means (46) comprise at least one ejection member (50), which is able to act on at least one mechanism (24) for controlling a gripper (20) in order to cause the latter to open.

8. System according to any one of the preceding claims, characterized in that said ejection device (44) is a first ejection device, the system (10) comprising at least one second ejection device (52) arranged upstream of the first ejection device (44).

9. System according to any one of the preceding claims, characterized in that the system (10) comprises at least one systematic ejection device (58) arranged downstream of the transfer point (T) for systematically ejecting any object conveyed by the first wheel (12) beyond the transfer point (T).

10. Method for conveying objects made of thermoplastic material and comprising a hollow body provided with a neck, the method using a first conveyor provided with a plurality of first means for individually grasping the objects to be conveyed along a first conveying path, and a second conveyor provided with a plurality of second means for individually grasping the objects to be conveyed along a second conveying path tangent to the first conveying path at a transfer point (T), the method comprising a step of synchronized operation in which each of the first grasping means arriving at the transfer point (T) cooperates with a complementary second transfer means in order to transfer an object from the first grasping means to the second grasping means, characterized in that it comprises a step of desynchronized operation in which the objects are ejected from the first grasping means before they arrive at the transfer point (T) by means of the system according to any one of Claims 1 to 9.