Device for ejecting preforms for a facility for manufacturing containers made of thermoplastic material from preforms by means of blow-moulding

Abstract

The invention relates to a device (11) for ejecting preforms (3) for a facility (1) for manufacturing (1) containers (2) made of thermoplastic material from preforms (3) by means of blow-moulding, the device having a conveying means (13) comprising a succession of gripping devices (14) which are intended to carry a preform (3) with a view to moving it in a vertical position along a substantially horizontal path, each preform (3) consisting of a substantially cylindrical body (4) and a neck (6) having at least one flange (7), the gripping devices (14) carrying the preforms (3) at the neck (6) thereof by engaging axially in the neck (6) of the preform (3) in order to hold it, and the gripping devices (14) comprising at least one mandrel (25) with a rotationally symmetrical axis, a spinner (15) mounted on one of the ends of the mandrel (25) and comprising at least one spinner nose (28) which is attached to the mandrel (25), the spinner nose (28) being intended to receive the neck (6) of the preform (3), and an ejector (29) which has a substantially cylindrical shape and of which one of the ends forms what is referred to as an ejection surface for the preform (3). The device is characterised in that it comprises at least one finger (35).

Description

1. Preform ejection device for a blow-molding plant for thermoplastic containers from preforms

[0001] The field of the invention is that of the design and manufacture of plastic containers. The present invention relates more particularly to a preform ejection device for an installation for manufacturing thermoplastic containers by blow molding from preforms, of the type comprising a series of transport elements which are each provided with at least one gripping device intended to carry a preform with a view to circulating it in a vertical position along a substantially horizontal path. State of the art

[0002] In the field of manufacturing plastic containers from preforms, systems for conveying said preforms are well known, of the type comprising a series of transport elements which are each provided with at least one gripping device intended to carry a preform with a view to circulating it in a vertical position along a path, oriented from upstream to downstream, inside the installation, of the type in which each gripping device is movable along a vertical axis relative to the transport element which carries it so that, when it is brought from a high, clear position to a low gripping position, it engages axially in the neck of the preform and grips it.

[0003] Such a system is described for example in document FR2794109.

[0004] Such conveyor systems are found in container blow molding machines in which the container is obtained by blow molding by introducing a preform previously made by injection molding into a blow mold. These machines are used, for example, for the manufacture of polyethylene terephthalate (PET) bottles.

[0005] This type of machine usually has an oven designed to heat the preforms inside at least one heating tunnel before the blowing operation.

[0006] This oven has a conveyor system that allows the preforms to circulate inside the heating tunnel.

[0007] The conveyor system may, for example, consist of a chain of link-shaped transport elements with continuous movement on itself.

[0008] To grip the preform, each conveying element comprises a gripping device which is axially movable relative to the conveying element and which, when brought from an extreme free position to an extreme gripping position, engages axially in the neck of the preform.

[0009] To achieve this, the preform must be brought below the corresponding transport element and must be kept perfectly vertical to it for the entire duration of the gripping operation. However, during this gripping operation, the transport element moves continuously, so the preform must also be moved continuously.

[0010] For this purpose, the preform is for example supported by a transport wheel comprising a disc which is rotated about its axis and which is provided, at its periphery, with substantially semi-circular notches. A guide in the form of an arc of a circle is arranged around a portion of the periphery of the disc so that a preform can be trapped radially between a notch in the disc and the guide. The preform then bears by a collar located at the base of its neck both on the disc and on the guide, the neck and the body of the preform extending respectively above and below the level of the disc. Thus, the preform is carried by the transport wheel and, due to the rotation of the disc, it is driven along a circular path.

[0011] The preforms and the transport elements are positioned on the transport wheel in such a way that each preform is arranged axially just vertically above the gripping device of one of the transport elements. Thus, the gripping device can be controlled, at a point on the circumference of the wheel, to its lower gripping position to grip the preform by its neck.

[0012] We therefore note that, at this point on the circumference of the wheel, the preform is still resting on the transport wheel and on the guide, which ends just after this point to allow the preform to follow the trajectory of the transport element.

[0013] In theory, at this point on the circumference of the wheel, the preform is therefore supported by its collar on the transport wheel and its position is perfectly defined by the notch in the disc in which it is trapped.

[0014] However, in practice, it is necessary to provide operating clearances between the preform, the disc, and the guide. The preform therefore has a certain latitude of movement relative to these two elements. However, it has been found that this latitude allows the preform to vibrate on the transport wheel, this being particularly noticeable in high-speed installations in which the speed of movement of the preform at the transport wheel is relatively high. These vibrations can affect the accuracy of the actual position of the neck of the preform at the gripping point so that, in certain cases, the gripping device and the neck may be slightly but sufficiently offset to the point of preventing the correct gripping of the preform.

[0015] It is already known to provide devices to improve the stability of the preform when it is gripped, for example in document FR2794109.

[0016] These devices, although satisfactory, nevertheless have certain limitations, particularly when the conveyor system is required to operate at very high speeds, so that certain preforms may be gripped incorrectly by a gripping device, which can cause significant malfunctions in the machine.

[0017] In order to overcome this drawback, a conveying system has already been devised which includes means for ejecting preforms which are incorrectly positioned on the associated gripping device. Such a system is described in particular in document EP1781460.

[0018] Said document EP1781460 discloses a conveying system in which each gripping device is linked in axial movement, upwards and downwards, to an associated bracket which is mounted to slide axially in one direction and which carries, at its lower axial end, a cam follower element, the bracket being biased axially downwards so that the cam follower element cooperates with a surface of a fixed cam which is provided to drive the gripping device from its high, released position to its low gripping position.Said bracket comprises a stud provided with a bearing surface which is designed to cooperate by sliding with a fixed ramp comprising a control surface inclined relative to the vertical and oriented generally upwards, when the gripping device occupies an intermediate axial position between its high, released position and its low gripping position, this intermediate axial position corresponding to an incorrect positioning of the gripping device in the preform, so that the fixed ramp drives the stud upwards and causes the axial sliding of the gripping device to its high, released position in order to allow the ejection of the associated preform, the fixed ramp extending axially to a determined height so that, when the gripping device occupies its low gripping position, the stud can circulate under the fixed ramp in a passage provided for this purpose.

[0019] This type of ejection device nevertheless has the disadvantage of not being suitable for very high production rates, i.e. production rates in excess of 60,000 bottles per hour and depositing grease in the preforms. Disclosure of the invention

[0020] One of the aims of the invention is therefore to remedy these drawbacks by proposing a device for ejecting preforms that are poorly positioned and / or have a defect after their heat treatment, of simple and inexpensive design, and allowing ejection of preforms at high speeds while avoiding a deposit of grease on the other preforms, i.e. the non-ejected preforms.

[0021] For this purpose and in accordance with the invention, there is provided a preform ejection device for an installation for manufacturing by blow molding containers made of thermoplastic material from preforms, of the type comprising a conveying means comprising a succession of gripping devices intended to carry a preform with a view to circulating it in a vertical position along a substantially horizontal path, each preform consisting of a substantially cylindrical body and a neck comprising at least one flange and an annular groove extending above said flange, the gripping device carrying the preforms at the neck of the latter by engaging axially in the neck of the preform to grip it, and said gripping devices comprising at least one mandrel with an axis of revolution, a spinner mounted on one of the ends of the mandrel and comprising at least one spinner nose which is fixed to the mandrel,said spinner nose being intended to receive the neck of the preform, and an ejector having a substantially cylindrical shape, one of its ends of which forms a so-called preform ejection surface; said device is remarkable in that it comprises at least one finger extending above the collar of the preforms or the ejector (29) of the gripping devices which circulate in line with said finger, in a so-called rest position, and an actuator cooperating with said finger to move the latter downwards in a substantially vertical plane from its rest position to a so-called active position in which said finger bears on the upper face of the collar of the preform or on the upper end of the ejector of the gripping devices to detach said preform from its gripping device before returning to its rest position.,

[0022] Preferably, said finger moves along a linear path.

[0023] According to an alternative embodiment, said finger moves along a curvilinear trajectory.

[0024] Furthermore, said finger is integral with a carriage mounted to move along a guide.

[0025] Preferably, the ejection device according to the invention comprises two fingers extending, in their rest positions, on either side of the neck of the preforms and above the collars of said preforms or the upper end of the ejector of the gripping devices.

[0026] Each finger is attached to a carriage mounted movably on a vertical guide.

[0027] Furthermore, each vertical guide consists of a vertical cylindrical rod.

[0028] In addition, each carriage is equipped with a ball or needle guide.

[0029] Preferably, each finger is formed by a horizontal triangular plate.

[0030] According to an alternative embodiment, each finger is formed by a substantially rectangular horizontal bar mounted to rotate around a vertical axis secured to the carriage.

[0031] Advantageously, each finger is provided with elastic return means.

[0032] Particularly advantageously, said actuator takes the form of a linear actuator.

[0033] Said linear actuator preferably consists of a linear electromagnetic actuator.

[0034] Said linear electromagnetic actuator comprises two rods whose free ends are respectively secured to a carriage.

[0035] Another object of the invention consists of an installation for manufacturing by blow molding containers made of thermoplastic material from preforms, of the type comprising a conveying means comprising a succession of gripping devices intended to carry a preform with a view to circulating in a vertical position along a substantially horizontal path, each preform consisting of a substantially cylindrical body and a neck comprising at least one flange, the gripping device carrying the preforms at the neck of the latter by engaging axially in the neck of the preform to grip it, said installation comprising at least one thermal conditioning unit and a forming unit; said installation being remarkable in that it comprises at least one ejection device according to the invention.

[0036] Other advantages and characteristics will emerge more clearly from the following description of several variant embodiments, given as non-limiting examples, of the preform ejection device according to the invention, with reference to the appended drawings in which:

[0037] is a schematic general view of a container production facility seen from above,

[0038] is a detail view of the medallion representing a preform,

[0039] is an overview of a spinner,

[0040] is a view of the nose of the tournette,

[0041] is a perspective view of the preform ejection device according to the invention,

[0042] is a side view of the preform ejection device according to the invention shown in the,

[0043] is a side view of the fingers of the preform ejection device according to the invention shown in Figures 5 and 6,

[0044] is a partial perspective view of a container production installation equipped with an alternative embodiment of the preform ejection device according to the invention,

[0045] is a partial perspective view of the variant embodiment of the preform ejection device according to the invention, shown in the,

[0046] is a partial front view of the variant embodiment of the preform ejection device according to the invention, shown in Figures 8 and 9,

[0047] is a top view of the variant embodiment of the preform ejection device according to the invention, shown in Figures 8 to 10.

[0048] Method of carrying out the invention

[0049] In the following description of the preform ejection device according to the invention, the same numerical references designate the same elements. The different views are not necessarily drawn to scale.

[0050] A schematic representation of an installation 1 for the mass production of containers 2 made of thermoplastic material from preforms 3 is shown.

[0051] In the remainder of the description, the preforms 3 and the containers 2 move in the production facility along a circulation path from upstream to downstream. The preforms 3 are moved in line along a heating path by conveying means which will be detailed later.

[0052] In a non-limiting manner, the containers 2 are bottles here. The thermoplastic material is for example formed here by polyethylene terephthalate, hereinafter referred to by its acronym "PET".

[0053] With reference to the, each preform 3 has a main axis "X" shown vertically on said. Each preform 3 has a cylindrical body 4 with a tubular wall closed at one of its axial ends by a bottom 5, and which is open at its other end by a neck 6, also tubular. The neck 6 is delimited downwards by a collar 7 and upwards by an upper end edge called a drinking rim 8.

[0054] The neck 6 generally has its final shape while the body 4 of the preform 3 is intended to undergo a relatively significant deformation to form the final container 2 during a forming step.

[0055] With reference to the, the container manufacturing installation comprises at least one thermal conditioning unit 9, a forming unit 10 and at least one ejection device 11 which will be detailed a little later.

[0056] The thermal conditioning unit 9, also called an oven, makes it possible to heat a succession of preforms 3 to a reference temperature. The reference temperature is chosen so that the body 4 of each preform 3 at the outlet of the thermal conditioning unit 9 is in a malleable state allowing deformation of the body 4 of the heated preform 3 in order to form the container 2 in the forming unit 10. The reference temperature is between the glass transition temperature and the crystallization temperature of the plastic material of the preform 3. In the case of PET, the reference temperature is, for example, close to 110°. The value of the reference temperature may vary depending on the product with which the container 2 will be filled or depending on the container filling technique. Thus, the reference temperature is different for hot filling or for a carbonated product, for example.

[0057] According to the embodiment shown in the, the thermal conditioning unit 9 is a scroll oven, in which the preforms 3 are transported to be exposed to a plurality of heating radiation sources 12.

[0058] For this purpose, the thermal conditioning unit 9 comprises a means 13 for conveying the preforms 3 through the thermal conditioning unit 9 along a heating path extending between an inlet and an outlet of the thermal conditioning unit 9.

[0059] With reference to Figures 1 and 3, said conveying means 13 comprises a succession of gripping devices 14, each being capable of supporting a preform 3, mounted on a chain, moving along the heating path in the thermal conditioning unit 9.

[0060] Each gripping device 14 is, for example, capable of receiving a preform 3 by fitting the neck 6 onto a turntable 15 as shown in the figure. Each turntable 15 is, for example, movable in rotation relative to the chain around an axis A of rotation coinciding with the main axis X of a preform 3 when the latter is supported by the turntable 15.

[0061] The thermal conditioning unit 9 also comprises a heating cavity which comprises two side walls facing each other and at least one of these walls being the one which supports several sources 12 of radiation arranged one above the other and one next to the other opposite the preforms.

[0062] In other words, the thermal conditioning unit 9 comprises a plurality of radiation sources 12 distributed along the heating path and at a height corresponding substantially to the height of the preforms so that the entire height of the body 4 of each preform 3 is exposed to the radiation sources 12 on the path of the preform in the thermal conditioning unit 9. By rotating the preforms 3 around their main axis X, the spinners 15 make it possible to uniformly expose the entire body 4 of the preforms to the radiation sources 12. In this particular embodiment, the radiation sources 12 are distributed on only one side of this path, and a reflective wall 16 is arranged on the other side of the heating path to reflect the heat towards the preforms 3.

[0063] In another embodiment not shown, the radiation sources 12 can be distributed on either side of the heating path without departing from the scope of the invention.

[0064] It should also be noted that the radiation sources 12 are arranged, where appropriate, so as not to subject the neck 6 to the heat emitted by the radiation sources 12. Indeed, as indicated previously, only the body 4 of the preform 3 is formed to produce the container 2. Consequently, the neck 6 must not be deformed during forming and must not be heated. To avoid heating the neck 6, the heat treatment unit 9 may comprise a ventilation device positioned at the necks 6 of the preforms 3 to evacuate the heat likely to be absorbed by said necks 6.

[0065] Each radiation source 12 is formed by an incandescent lamp emitting infrared radiation.

[0066] In another embodiment, each radiation source 12 is a laser diode emitting infrared radiation.

[0067] In other words, each radiation source 12 is a laser (for example laser diodes) emitting in the infrared and organized by juxtaposition and / or superposition to form one or more matrices.

[0068] In another embodiment, each radiation source 12 is a microwave generator.

[0069] Then, once the preform 3 has been thermally conditioned through the thermal conditioning unit 9, it is transferred to the forming unit 10 to be formed there.

[0070] Said unit 10 for forming containers 2 from preforms 3, with reference to the, consists of a forming wheel 17 rotating a plurality of blowing stations 18 from an inlet to an outlet, at which a succession of containers 2 are formed from the preforms 3, then are extracted, as shown in the. The axis of rotation of the forming wheel 17 is, for example, substantially parallel to the main axis X of the preforms 3 when they are transported by the forming wheel 17.

[0071] Each blowing station 18 comprises a mold 19 forming a molding cavity having the shape of the container 2 to be formed and arranged to receive a preform 3 so that the body 4 of the preform 3 extends into the molding cavity.

[0072] The container manufacturing installation also comprises at least one ejection device 11 for the preforms 3, namely an ejection device 11 positioned in the heat treatment unit 9, along the heating path, and / or a second ejection device 11 positioned at the outlet of the heat treatment unit 9, i.e. between the heat treatment unit 9 and the forming unit 10, along the circulation path. Said ejection device 11 will be described in more detail in the remainder of the description.

[0073] With reference to the, the gripping device 14 usually comprises a support also called a link 20, which although shown individually on the, is in fact integrated into a chain which comprises a multitude of such links 20.

[0074] In this embodiment, the link 20, preferably metallic (e.g. steel), comprises two superimposed branches 21, 22, which project laterally from a core 23. The branches 21, 22 are pierced with coaxial holes 24 which jointly define a main axis.

[0075] The gripping device 14 further comprises a mandrel 25 with an axis of revolution mounted in the holes 24 of the link 20 following a pivot connection sliding relative to the link 20, the main axis of the holes 24 and the axis of revolution of the mandrel 25 thus being coaxial, a pinion 26 integral in rotation with one of the free ends of the mandrel 25, the pinion 26 being advantageously formed on a coil-shaped end piece 27, force-fitted onto the mandrel 25, and a turntable 15 mounted on the other end of the mandrel 25.

[0076] Said spinner 15 comprises at least one spinner nose 28 which is fixed to the mandrel 25 in a removable manner, in this case by means of a bayonet (not shown in the figure), said spinner nose 28 being intended to receive the neck 6 of the preform 3, and an ejector 29 secured to the link 20 by removable fixing means well known to those skilled in the art.

[0077] Said ejector 29 has a substantially cylindrical shape and comprises at one of its ends at least one surface called ejection surface of the preform 3.

[0078] The mandrel 25 and the spinner nose 28 extend coaxially with the ejector 29 in such a way that the free end of the spinner nose 28 projects from the ejector 29.

[0079] According to an alternative embodiment, not shown in the figures, the link 20 can be a linear motor also comprising at least one hole and in which the mandrel, the turntable, the pinion are mounted on a sliding pivot, without however departing from the scope of the invention.

[0080] In another embodiment not shown, the conveying means 13 comprises for example a succession of gripping devices 14, each being capable of supporting a preform 3, mounted on a shuttle of the linear motor type circulating on a closed magnetic loop. The movement of each of these shuttles is then controlled independently of each other by a control unit (not shown in the figures).

[0081] It is understood that the turntable 15 is a mobile assembly intended to ensure the gripping of a preform 3 by its neck 6, and mounted on the link 20 with two degrees of freedom: a translation along the main axis A and a rotation around the main axis A.

[0082] With reference to the, the spinner nose 28 comprises a radially expanding head 30 which is force-fitted inside the neck 6 of the preform 3, a radiator 31, and a shaft 32.

[0083] Said cylindrical head 30 with vertical axis "A" has an external diameter slightly smaller than the internal diameter of the neck 6 of the preform 3 so that there remains a radial sliding clearance between the head 30 and the neck 6 of the preform 3 when the head 30 is fitted into said neck 6.

[0084] Preferably, the head 30 comprises rings 33 which are in the form of ring sectors. Each ring 33 is received so as to slide radially in a radial housing of the head 30 between a position called retracted towards the axis "A" of the head 30 in which the spinner 15 can slide vertically relative to the neck 6 and a position called radial expansion in which they are capable of being clamped against the internal cylindrical face of the neck 6 to retain the preform 3 by friction.

[0085] The rings 33 are elastically constrained towards their expansion position by means of an elastic ring which is interposed radially between the bottom of the housing made in the head and the ring 33.

[0086] Furthermore, the head 30 is delimited vertically downwards by a section of larger diameter delimiting an annular shoulder face which is turned downwards and which forms a positioning face against which the rim 8 is received in vertical abutment when the head 30 is fitted into the neck 6.

[0087] The radiator 31 is arranged above the head 30 and comprises fins 34 which have a generally cylindrical shape with a main vertical axis A, coaxial with the axis A of the head and whose diameter is equivalent to the diameter of the section with a larger diameter than the head 30.

[0088] The shaft 32 is fixed at one of these ends to the radiator 31 and head 30 assembly, while the other end of the shaft 32 is fixed to the mandrel 25 in a removable manner, in this case by means of a bayonet (not shown in the figures), the head 30, the radiator 31, the shaft 32 and the mandrel 25 being coaxial.

[0089] In order to remove the preforms 3 which are incorrectly positioned on the associated gripping device 14 before their heat treatment and / or to eject the preforms 3 which, at the end of their heat treatment, have a defect likely to prevent correct blowing in the forming unit 10, with reference to FIGS. 1 and 5 to 7, the installation advantageously comprises at least one ejection device 11 for the preforms 3, namely a first ejection device 11 positioned in the heat treatment unit 9, along the heating path, and / or a second ejection device 11 positioned at the outlet of the heat treatment unit 9, i.e. between the heat treatment unit 9 and the forming unit 10, along the circulation path.

[0090] With reference to Figures 5 to 7, said ejection device 11 comprises at least one finger 35 extending above the collar 7 of the preform 3 in a so-called rest position and an actuator 36 cooperating with said finger 35 to move the latter downwards in a substantially vertical plane from its rest position to a so-called active position in which said finger 36 bears on the upper face of the collar 7 of the preform 3 to detach said preform 3 from its gripping device 14 before returning to its rest position.

[0091] More precisely, said ejection device 11 comprises a plate 37 capable of being secured to the frame of the heat treatment unit 9, for example, and carrying said actuator 36 which comprises, in this particular embodiment, two vertical rods 38 at the upper end of which two fingers 35 are secured. Said fingers 35 extend on either side of the axis of the preforms 3, along their path, above the collars 7 of said preforms 3 in the so-called rest position.

[0092] Each finger 35 and / or rod 38 of the actuator 36 is integral with a carriage 39 mounted to move along a vertical guide 40. Thus, the ejection device 11 comprises two vertical guides 40 in the form of cylindrical rods extending parallel to the vertical rods 38 of the actuator 36 and along which the carriages 39 carrying the fingers 35 slide. Said guides 40 are integral with the plate 37.

[0093] In order to facilitate the sliding of the carriages 38 along the guides 39, said carriages advantageously comprise a ball or needle guide.

[0094] In this particular embodiment, each finger 35 is formed by a triangular plate extending substantially horizontally and the tip of which is substantially oriented towards the axis of the preforms 3.

[0095] It is obvious that the ejection device 11 according to the invention could comprise only a single finger 35 and each finger 35 could have any shape without departing from the scope of the invention.

[0096] Particularly advantageously, said actuator 36 takes the form of a linear actuator and more particularly the form of a linear electromagnetic actuator. Thus, the speed of movement of the fingers 35 provided by said actuator makes it possible to eject the preforms one by one at high rates, i.e. rates greater than 60,000 bottles per hour. In addition, the use of such an actuator 36 makes it possible to avoid any projection of grease onto the preforms.

[0097] It is obvious that said actuator 36 may consist of any other equivalent actuator well known to those skilled in the art without departing from the scope of the invention.

[0098] Thus, when a preform 3 is incorrectly positioned on the associated gripping device 14 before its heat treatment and / or when a preform 3 having a defect is detected by an appropriate sensor, not shown in the figures, the actuator 36 is activated in such a way that the fingers 35 which, in the rest position, extend above the collar 7 of the preforms, are moved rapidly along a linear trajectory downwards to bear on the upper face of the collar 7 and eject the preform 3 from the head 30 of the spinner nose 28 of its gripping device 14, said fingers 35 returning to their initial rest position quickly after ejection, ready for a new ejection of a preform.

[0099] According to an alternative embodiment, not shown in the figures, the ejection device 18 could comprise one or two fingers 35 mounted at the end of a lever articulated around an axis, the other end of the lever being integral with the rod 38 of the actuator 36 so that said finger 35 moves along a curvilinear trajectory without departing from the scope of the invention.

[0100] According to another variant embodiment, with reference to figures 8 to 11, said ejection device 11 is, in the same way as previously positioned along the conveying means 13 of the manufacturing installation 1) by blowing containers made of thermoplastic material from preforms, said conveying means 13 comprising a succession of gripping devices 14 intended to carry a preform, not shown in figures 8 to 11, with a view to circulating it in a vertical position along a substantially horizontal path.

[0101] Said gripping devices 14 comprise at least one mandrel 25 with an axis of revolution, a spinner 15 mounted on one of the ends of the mandrel 25 and comprising at least one spinner nose 28 which is fixed to the mandrel 25, said spinner nose 28 being intended to receive the neck 6 of the preform 3, and an ejector 29 having a substantially cylindrical shape, one of its ends of which forms a so-called ejection surface of the preform 3.

[0102] In this variant embodiment, said ejection device 11 comprises at least one finger 35 extending above the upper end of the ejector 29 of the gripping devices 14 in a so-called rest position and an actuator 36 cooperating with said finger 35 to move the latter downwards in a substantially vertical plane from its rest position to a so-called active position in which said finger 36 bears on the upper end of the ejector 29 of the gripping devices 14, the ejector 29 then moving downwards, to detach said preform 3 from its gripping device 14 before returning to its rest position.

[0103] More precisely, said ejection device 11 comprises a plate 37 capable of being secured to the frame of the heat treatment unit 9, for example, and carrying said actuator 36 which comprises, in this particular embodiment, two vertical rods 38 at the upper end of which two fingers 35 are secured. Said fingers 35 extend on either side of the axis of the preforms 3 and the ejectors 29, along their path, above the upper end of the ejector 29 of the gripping devices 14 in the so-called rest position.

[0104] Each finger 35 and / or rod 38 of the actuator 36 is integral with a carriage 39 mounted to move along a vertical guide 40. Thus, the ejection device 11 comprises two vertical guides 40 in the form of cylindrical rods extending parallel to the vertical rods 38 of the actuator 36 and along which the carriages 39 carrying the fingers 35 slide. Said guides 40 are integral with the plate 37.

[0105] In order to facilitate the sliding of the carriages 38 along the guides 39, said carriages advantageously comprise a ball or needle guide.

[0106] In this particular embodiment, each finger 35 is formed by a substantially rectangular horizontal bar mounted to rotate around a vertical axis 41 secured to the carriage 39 and whose longitudinal axis is substantially oriented towards the axis of the preforms 3 and the ejectors 29.

[0107] Advantageously, each finger 35 is provided with elastic return means, not shown in the figures, so that, if a finger 35 strikes an ejector 29 during its movement, said finger 35 is able to pivot around its axis 41 then to return to its initial position. It will be observed that said elastic return means may consist of any elastic return means well known to those skilled in the art.

[0108] Furthermore, the device comprises means for detecting, not shown in the figures, the position of each finger 35 so that, if a finger 35 is not in the active position in the high position and / or in the low position of the carriage, a signal is transmitted to the automaton indicating a fault in the ejection of the preform(s) and so that the latter proceeds to stop the installation in order to correct the problem.

[0109] It is obvious that the ejection device 11 according to the invention could comprise only a single finger 35 and each finger 35 could have any shape without departing from the scope of the invention.

[0110] Particularly advantageously, said actuator 36 takes the form of a linear actuator and more particularly the form of a linear electromagnetic actuator. Thus, the speed of movement of the fingers 35 provided by said actuator makes it possible to eject the preforms one by one at high rates, i.e. rates greater than 60,000 bottles per hour. In addition, the use of such an actuator 36 makes it possible to avoid any projection of grease onto the preforms.

[0111] It is obvious that said actuator 36 may consist of any other equivalent actuator well known to those skilled in the art without departing from the scope of the invention.

[0112] Thus, when a preform 3 is incorrectly positioned on the associated gripping device 14 before its heat treatment and / or when a preform 3 having a defect is detected by an appropriate sensor, not shown in the figures, the actuator 36 is activated in such a way that the fingers 35 which, in the rest position, extend above the upper end of the ejector 29 of the gripping devices 14, are moved rapidly along a linear downward trajectory to bear on the upper end of the ejector 29 of the gripping devices 14 and cause a downward movement of said ejector 29, the lower end of which bears on the neck 6 of the preform 3 and, ultimately, eject said preform 3 from the head 30 of the spinner nose 28 of its gripping device 14, said fingers 35 returning to their initial rest position rapidly after ejection, ready for a new ejection of a preform.

[0113] Finally, it is clear that the examples just given are only specific illustrations and are in no way limiting as to the fields of application of the invention.

Claims

Device (11) for ejecting preforms (3) for a manufacturing installation (1) by blowing containers (2) made of thermoplastic material from preforms (3), of the type comprising a conveying means (13) comprising a succession of gripping devices (14) intended to carry a preform (3) in order to circulate it in a vertical position along a substantially horizontal path, each preform (3) consisting of a substantially cylindrical body (4) and a neck (6) comprising at least one flange (7), the gripping devices (14) carrying the preforms (3) at the neck (6) of the latter by engaging axially in the neck (6) of the preform (3) to grip it and said gripping devices (14) comprising at least one mandrel (25) with an axis of revolution, a spinner (15) mounted on one of the ends of the mandrel (25) and comprising at least one nose of turntable (28) which is fixed to the mandrel (25),said spinner nose (28) being intended to receive the neck (6) of the preform (3), and an ejector (29) having a substantially cylindrical shape, one of its ends of which forms a so-called ejection surface of the preform (3), characterized in that it comprises at least one finger (35) extending above the collar (7) of the preforms or the ejector (29) of the gripping devices which circulate in line with said finger (35), in a so-called rest position, and an actuator (36) cooperating with said finger (35) to move the latter downwards in a substantially vertical plane from its rest position to a so-called active position in which said finger (35) bears on the upper face of the collar (7) of the preform (3) or on the upper end of the ejector (29) of the gripping devices (14) to detach said preform (3) from its device gripping (14) before returning to its rest position., Preform ejection device according to claim 1 characterized in that said finger (35) moves along a linear trajectory. Preform ejection device according to claim 1 characterized in that said finger (35) moves along a curvilinear trajectory. Preform ejection device according to any one of claims 1 to 3, characterized in that said finger (35) is integral with a carriage (39) mounted to move along a guide (40). Preform ejection device according to any one of claims 1 to 4, characterized in that it comprises two fingers (35) extending, in their rest positions, on either side of the neck (7) of the preforms (3) and above the collars (7) of said preforms (3) or the upper end of the ejector (29) of the gripping devices (14). Preform ejection device according to claim 5 characterized in that each finger (35) is integral with a carriage (39) mounted movably on a vertical guide (40). Preform ejection device according to claim 6 characterized in that each vertical guide (40) consists of a vertical cylindrical rod. Preform ejection device according to any one of claims 5 to 7, characterized in that each carriage (39) is provided with a ball or needle guide. Preform ejection device according to any one of claims 5 to 8, characterized in that each finger (35) is formed by a horizontal triangular plate. Preform ejection device according to any one of claims 6 to 8, characterized in that each finger (35) is formed by a substantially rectangular horizontal bar mounted in rotation around a vertical axis integral with the carriage (39). Preform ejection device according to claim 10 characterized in that each finger (35) is provided with elastic return means. Device according to any one of claims 1 to 11, characterized in that said actuator (36) takes the form of a linear actuator. Device according to claim 12 characterized in that said linear actuator (36) consists of a linear electromagnetic actuator. Device according to claim 12 and any one of claims 6 to 11, characterized in that said linear electromagnetic actuator (36) comprises two rods (38) whose free ends are respectively secured to a carriage (39). Manufacturing installation (1) by blowing containers (2) made of thermoplastic material from preforms (3), of the type comprising a conveying means (13) comprising a succession of gripping devices (14) intended to carry a preform (3) with a view to circulating it in a vertical position along a substantially horizontal path, each preform (3) consisting of a substantially cylindrical body (4) and a neck (6) comprising at least one flange (7), the gripping device (14) carrying the preforms (3) at the neck (6) of the latter by engaging axially in the neck (6) of the preform (3) to grip it, said installation (1) comprising at least one thermal conditioning unit (9) and a forming unit (10), characterized in that it comprises at least one ejection device (11) according to any one of claims 1 to 14.

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