FR3140360A1 - PREFORM TRANSFER METHOD ON A CONVEYOR - Google Patents

Abstract

The invention relates to a method for transferring containers, and in particular preforms (12) made of thermoplastic material, comprising a neck (16) having a main axis (A), opening through an opening (24) delimited by a free edge of the neck called "drinking (26)", the container being transferred to a conveyor (36) in which the container is held by a gripping member (38) fitted axially with the neck (16) during a dressing operation, characterized in that, during the dressing operation, the collar (16) is clamped axially between a reaction face (68) facing the rim (26) and a face (70) for maintaining axially facing the reaction face (68), the holding face (70) resting against the rim (26). Figure for abstract: Figure 13

Description

PREFORM TRANSFER METHOD ON A CONVEYOR Technical field of the invention

The invention relates to a method of transferring containers, and in particular preforms made of thermoplastic material, comprising a neck having a main axis, opening through an opening delimited by a free edge of the neck called "drinking", the container being transferred to a conveyor in which the container is held by a gripping member fitted axially with the neck during a dressing operation.

Technical background

The present invention relates to improvements made to a method of transferring containers or preforms having a neck, in particular bottles, on a conveyor in which each container is held by an individual gripping member fitted with its neck. The gripping members travel along a closed loop path to transport containers from a loading point to an unloading point. The gripping members are generally made in the form of mandrels pressed axially by force into the neck of the container, during an operation called the dressing operation.

These gripping members are mutually spaced at a predetermined pitch over a section of their path passing through the loading point and the unloading point of the preforms. The containers are brought to the loading point one after the other, spaced at a predetermined pitch.

Such a transfer process is particularly suitable for container manufacturing and/or filling installations. Thus, in container manufacturing facilities, preforms are transported by such a conveyor through a heating station before the heated preforms are transformed into final containers by a forming operation, in particular by biaxial stretching.

In this type of installation, the transport of the preforms to the loading point is commonly ensured by transfer wheels, many embodiments of which are known.

Each preform is loaded onto an associated gripping member during the dressing operation, during which the gripping member is forced into the neck of the preform, the preform being supported by the transfer wheels.

Furthermore, in the stations for heating the thermoplastic material constituting the preforms, which are used in the container manufacturing installations, the transfer of the preforms can be ensured by trays with notches or clamps which grip the preforms and bring them under the chucks in motion.

In these known installations, the path of the gripping members in plane projection is tangent at a single point of tangency with the trajectory of the preforms carried by the transfer wheel.

The rotational drive of the transfer wheel and the vertical translation drive of the gripping members are synchronized so that a gripping member and a preform carried by the transfer wheel are presented in synchronism at the point of tangency, at the balance of each other. At this single point of tangency, the dressing operation is carried out. The descent of the gripping member previously reassembled into the retracted position and its nesting in the neck of the underlying preform are controlled for example by a system of cams.

However, the dressing operation must be carried out very quickly because the preforms only cross the trajectory of the gripping members at a single point. Such a dressing operation is not suitable for a high operating rate of the loading device. Indeed, the higher the speed of movement of the gripping members, the more quickly the dressing operation must be carried out. However, at high speeds, the gripping member is likely to be insufficiently fitted into the neck of the preform. The preform then risks falling from the gripping member.

To solve this problem, it has already been proposed to equip the conveyor with double grippers which move together with an associated gripping member over a portion of the path comprising the loading point and the unloading point. Thus, instead of carrying out the dressing operation only at the tangency point, each double gripper grips a preform at the tangency point. The double-clamp grips the neck of the preform on either side of the collar so as to block the neck vertically in both directions by direct contact with the collar in order to guarantee the correct holding of the preform, even when the latter is not perfectly centered in relation to the gripping member. The operation of covering the gripping member is then carried out along a common path portion of the double pliers and the associated mandrel. Thus, the dressing operation is spread over the entire portion of the journey instead of being carried out at a single point. This dressing operation can therefore be carried out over a sufficiently long period to guarantee reliable nesting of the preforms, even in the event of an increase in throughput.

When the preforms are removed from the heating station, the neck of the preform is again grasped by the double gripper to be able to disengage the mandrel, during a so-called stripping operation, and transfer the preform to an exit conveyor.

However, the double clamp occupies the only two spaces which allow a preform to be correctly grasped by its neck by means of pliers, namely the area located directly under the collar, and a groove located directly above the collar, this groove being generally intended to subsequently receive a tamper-evident ring from a container cap. For this reason, we will subsequently call this groove “inviolability throat”.

However, in certain installations, it is proposed to grasp the preforms leaving the heating station by means of articulated arms fitted with grippers to transfer the preforms in a single step from the unloading point of the heating station to the station following, for example the biaxial stretch forming station. However, with the double-clamp device, it is not possible to grasp the collar either below the collar or through the tamper-evident groove.

To remedy this problem, it is necessary to provide a notched output wheel which is suitable for unclipping the preforms from the double clamp, then a second wheel rotating in the right direction before the preforms are grasped by the mobile arms equipped with pliers. Such a solution is expensive, bulky and extends the travel time of the preforms through the installation.

There is therefore a need to find a method allowing both reliable nesting of the preforms on the conveyor of the heating station and offering the possibility of quickly transferring the preforms to the station following the heating station.

The invention proposes a method for transferring containers, and in particular preforms made of thermoplastic material, comprising a neck having a main axis, opening through an opening delimited by a free edge of the neck called "drinking", the container being transferred to a conveyor in which the container is held by a gripping member fitted axially with the neck during a dressing operation.

The method carried out according to the teachings of the invention is characterized in that, during the dressing operation, the collar is clamped axially between a reaction face turned towards the rim and a holding face axially facing each other. of the reaction face, the holding face being supported against the rim.

According to another aspect of the process carried out according to the teachings of the invention, the reaction face is in contact with a collar of the neck.

According to another aspect of the method carried out according to the teachings of the invention, each gripping member of the conveyor comprises an ejection member mounted sliding axially on the gripping member between an extreme dressing position allowing the axial nesting of the gripping member with the neck and an extreme stripping position towards which the ejection member is slid so that a contact face of the ejection member presses on the edge of the neck to disengage it entirely from the gripping member, the holding face being formed by the contact face of the ejection member.

The invention also proposes a device for implementing the method according to the teachings of the invention, the device comprising:

- at least one transport fork of a container which moves in coincidence with an associated gripping member of the conveyor, an upper face of the transport fork forming the reaction face;

- means for distributing the preforms which comprise means for individually receiving each container so as to successively lead each container to a point of tangency with the trajectory of the transport fork at which the container is transferred to the transport fork;

- the transport fork being mounted to slide axially between a transfer position in which the transport fork is positioned at the same level as the individual receiving means for gripping the neck when the container is carried by the distribution means and a position of nesting in which the neck of a container carried by the transport fork is intended to be nested with the gripping member.

The device produced according to the teachings of the invention is characterized in that it comprises a sliding control mechanism of the holding face which is slidably mounted on a carriage on which the associated transport fork is fixed so that, when the control mechanism is immobilized relative to the carriage, the sliding of the transport fork jointly causes the sliding of the holding face.

According to another aspect of the device produced according to the teachings of the invention, the sliding stroke of the control mechanism relative to the carriage is less than the sliding stroke of the ejection member between its two extreme positions, the mechanism being controlled between a neck tightening position in which it is brought closer to the transport fork to urge the holding face towards the reaction face and a neck release position in which it is moved away from the transport fork to no longer stress the face holding it tight against the rim.

According to another aspect of the device produced according to the teachings of the invention, the transport fork is controlled in sliding by a cam path fixed relative to the ground which cooperates with a cam follower which is carried by the carriage.

According to another aspect of the device produced according to the teachings of the invention, the transport fork is elastically returned to its upper nesting position.

According to another aspect of the device produced according to the teachings of the invention, the sliding control mechanism of the holding face comprises a cam follower which is mounted sliding axially in the carriage, and which cooperates with a fixed cam path by relationship to the ground.

According to another aspect of the device produced according to the teachings of the invention, the sliding control mechanism of the holding face is elastically returned to its clamping position.

According to another aspect of the device produced according to the teachings of the invention, the control mechanism comprises a control fork slidably mounted in the carriage and which cooperates with one face of the ejection member to bias the ejection member down.

According to another aspect of the device produced according to the teachings of the invention, the device comprises a plurality of transport forks mounted integrally in rotation with a drive wheel around which the gripping members are indexed during their movement, each carriage being mounted sliding axially on the drive wheel.

Brief description of the figures

Other characteristics and advantages of the invention will appear during reading of the detailed description which follows, for the understanding of which we will refer to the appended drawings briefly described below.

There is a top view which schematically represents a container manufacturing installation produced according to the teachings of the invention.

There is a perspective view which represents a preform intended to supply the installation of the .

There is an axial sectional view which represents a gripping member of the conveyor of a heating station of the installation of the , the gripping member being equipped with a preform ejection member in an extreme dressing position.

There is a view similar to that of the , in which the preform ejection member occupies an extreme stripping position.

There is a perspective view which shows a drive wheel of the conveyor device of the heating station of the and in which a preform is held both by a transport fork and by an associated transport member.

There is a perspective view which represents a device which equips the drive wheel of the and which makes it possible to carry out an operation of dressing or undressing the preforms in relation to a transport member of the conveyor of the heating station, a carriage of the device being represented in transparency to allow the different components of said device to be clearly seen.

There is a detailed view which represents an upper end of the device of the , said end comprising a transport fork and a control fork.

There is a developed profile view of the stroke of a device of the along part of a circular path guided by the drive wheel.

There is a perspective view which shows an input wheel, a transfer wheel and part of the drive wheel of the installation of the .

There is a larger scale detail view of the which represents a notch in the transfer wheel passing at a point P3 of the path of the preforms as indicated in , corresponding with a transport fork.

There is a perspective view which represents a preform supported by a transport fork at point P3 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork between points P3 and P1 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork at point P1 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork at point P5 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork just before its arrival at point P6 of its journey as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork at point P6 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a perspective view which represents a preform supported by a transport fork at point P2 of its path as indicated in .

There is a detailed view similar to that of the which represents the preform and the transport fork in the position shown in .

There is a top view of detail 25 of the .

Detailed description of the invention

In the remainder of the description, we will use, on a non-limiting basis, a vertical orientation which is indicated by the arrow “V” in the figures directed from bottom to top. The vertical direction is used here as a geometric reference. It is directed parallel to the direction of nesting of the preforms 12 with gripping members 38. A plane extending orthogonally to the vertical direction “V” will be called a “horizontal” plane.

Subsequently, elements having an identical structure or similar functions will be designated by the same reference.

We represented at the part of an installation 10 for manufacturing final containers, in particular bottles, by biaxial stretching of initial containers made of thermoplastic material.

The initial containers here are preforms 12 which are made of a thermoplastic material, such as polyethylene terephthalate (PET), and which are intended to be transformed into final containers, such as bottles, after a first heating operation to soften the thermoplastic constituting them, then a second blowing or stretch-blowing operation, to shape the preform 12 into a final container.

We represented at the such a preform 12. The preform 12 has a main axis “A” which extends here in the vertical direction “V”.

The preform 12 comprises a body 14 which extends vertically along the axis “A”. The body 14 opens vertically upwards via a neck 16 and is closed at the opposite end by a bottom 18. The body 14 here has a generally cylindrical shape.

The neck 16 includes a support surface 20 by means of which the preform 12 can be supported. Advantageously, the neck 16 of the preform 12 comprises at least one flange 22 which extends in a horizontal plane relative to the axis “A”. The collar 22 is located in a junction zone of the neck 16 with the body 14. It extends radially projecting outwards, in particular with respect to the body 14. The support surface 20 of the preform 12 is formed by a lower annular face of said flange 22. The flange 22 also has an upper annular face 23 opposite the support surface 20.

The neck 16 has an upper end edge which circumferentially delimits an opening 24 for access to the interior of the body 14 of the preform 12. This edge will subsequently be called “drinking surface 26”.

In the exemplary embodiment, the neck 16 has on its external cylindrical surface a thread 28 intended to allow the subsequent closing of the container, for example by a screw cap. Alternatively, the thread can be replaced by elastic engagement means with a plug.

The neck 16 also includes an annular groove 30 which is arranged directly above the collar 22. In a non-limiting manner, this groove 30 is for example intended to receive a tamper-evident ring temporarily secured to a cap until opening the container. This groove will subsequently be called “inviolability groove 30”.

The description of the neck 16 which has just been made also applies to a container obtained from such a preform 12. The neck 16 of the preform 12 already has its final shape. Indeed, we recall that the neck 16 having its final shape, only the body 14 of the preform 12 is intended to undergo a forming operation to conform the preform 12 into a final container.

Referring again to the , the manufacturing installation 10 here comprises a heating station 32 and a forming station 34, in particular by stretch-blowing.

The heating station 32 is equipped with a conveyor 36 which makes it possible to transport the preforms 12 in line along a transport path from a point “P1” for loading the preforms 12 to an unloading point “P2”. preforms 12. The path of the preforms 12 passes through at least one heating zone (not shown) in which the body 14 of each preform 12 is heated to a temperature suitable for forming the preform 12 into a final container in the forming station 34.

For this purpose, the conveyor 36 comprises gripping members 38 which are intended to be fitted in the direction of the axis “A” in the neck 16 of a preform 12.

The gripping members 38 move along a closed loop 39 extending in a horizontal plane. A portion of the closed loop 39 forms the transport path of the preforms 12. For this purpose each gripping member 38 is carried by a transport element (not shown).

Each transport element is for example a link. All the transport elements are then articulated to each other to form a closed flexible element such as an endless transport chain extending in a horizontal plane.

In this case, the gripping members 38 are driven by at least one driving wheel around which the chain is meshed. Each gripping member 38 carried by the chain is spaced from the next gripping member 38 by a determined step “S”.

As a variant of the invention not shown, the transport chain makes it possible to compact the preforms by folding like an accordion when it passes through a heating zone as described in detail in document EP-B1-2,623,439.

In a variant not shown of the invention, instead of forming links of a chain, each transport element is formed by an independent shuttle. The conveying device then comprises at least one linear motor to control the movement of each shuttle independently of each other along the closed loop 39. Such a conveying device for a heating station is for example described in document FR-A1-3.035.651.

In the latter case, the linear motor comprises a stator comprising a series of windings which are distributed along the closed circuit. Each winding is individually controlled to locally induce a magnetic field independently of the other windings which acts on the shuttles to cause their movement. For this purpose, the shuttles carry a magnetic element capable of interacting with the magnetic field emitted by the stator windings. The windings are for example controlled by an electronic control unit (not shown) which is programmed appropriately.

The linear motor thus comprises a single stator, formed by the magnetic path, and several shuttles, forming "rotors", controlled independently along said stator.

Whatever the embodiment chosen for the transport elements, each gripping member 38 is here formed by a mandrel, as shown schematically in Figures 3 and 4. The gripping member 38 is capable of being fitted vertically in the neck 16 of the preform 12 passing through its opening 24, during a dressing operation, with a tight fit to ensure the immobilization of the preform 12 by friction with an internal cylindrical wall 17 of the neck 16.

According to a non-limiting embodiment shown in Figures 3 and 4, the gripping member 38 here comprises at least three segments 40, two of which are visible in section at the , which are arranged around axis “A”. Each segment 40 is pushed radially outwards into an expanded position by a ring 42 made of an elastomeric material which is received in a central groove 44 of the gripping member 38. Thus, each segment 40 is capable of being pushed radially by the ring 42 against the internal cylindrical wall 17 of the neck 16 to grip the preform 12 by friction. In this regard, the portion of the gripping member 38 intended to be received tight inside the neck 16 has, in the expanded state, an external diameter which is slightly greater than the internal diameter of the neck 16 of the preforms 12 intended to be taken care of.

Thus, during an operation of covering the preform 12 by the gripping member 38, the gripping member 38 is forcibly inserted vertically inside the neck 16 of the preform 12 by relative vertical sliding of the gripping member 38 relative to the preform 12, which causes a retraction of the segments 40 against the elastic restoring force exerted by the ring 42, as shown in .

Each gripping member 38 is more particularly carried by a rod 46, also called a spinner, with a vertical axis which extends vertically downwards from the transport element. The rod 46 is coaxial with the axis “A” of the preform 12 carried by the gripping member 38.

The rod 46 is for example mounted to rotate around its axis relative to the transport element in order to be able to rotate the preform 12 on itself around its axis “A” during its transport by the conveyor 36.

Each gripping member 38 also includes an ejection member 48 which has a lower contact face 50 which is intended to come to bear against the rim 26 of a preform 12 carried by the gripping member 38.

In the embodiment shown in the figures, the ejection member 48 is in the form of a sleeve delimited vertically downwards by the contact face 50 which has a continuous annular shape. The ejection member 48 is arranged around the rod 46.

Alternatively, the ejection member is formed of several fingers, for example three fingers, a lower end of which forms a portion of the contact face 50. The contact face 50 is then discontinuous.

The ejection member 48 is mounted sliding vertically on the gripping member 38 between:

- an extreme clothing position in which the gripping member 38 projects vertically downwards relative to the contact face 50 to allow the vertical nesting of the gripping member 38 with the neck 16, as is illustrated to the ; And

- an extreme undressing position in which the contact face 50 is located below the gripping member 38 so that the contact face 50 of the ejection member 48 presses on the rim 26 of the neck 16 to remove it entirely from the gripping member 38, as is illustrated in .

The ejection member 48 here comprises several guide columns 52, for example three columns 52, which extend vertically upwards. Each column 52 is fixed relative to the ejection member 48.

Each guide column 52 is received in a sliding manner vertically in an associated passage orifice 54 of a radial plate 56 which extends radially projecting from the rod 46 so that each column 52 projects vertically above a upper face of the plate 56. The plate 56 is integral with the rod 46, it is for example made in one piece with the rod 46.

An elastic return means 58, here a helical spring, is interposed between a shoulder 61 of the upper end of each column 52 and the upper face of the plate 56. The elastic return means 58 thus makes it possible to elastically return the member 48 ejection towards its extreme dressing position.

We represented at the a curved portion 39A of the closed loop 39 along which the gripping members 38 move. This portion includes the loading point “P1” and the unloading point “P2”. Along this portion of the closed loop 39, the gripping members 38 are held at a pitch “S” from each other by a drive wheel 60.

When the transport elements form a chain, this drive wheel 60 can also have a function of guiding and/or driving the transport chain.

The drive wheel 60 is mounted to rotate around a vertical central axis "D" and it is rotated in an anti-clockwise direction with reference to the .

The turning portion 39A of the closed loop 39 follows a peripheral rim portion of the drive wheel 60. The turn portion 39A here forms a semi-circle.

The closed loop 39 also includes a straight downstream portion 39B which is arranged tangentially to the drive wheel 60 downstream of the turning portion 39A in the direction of anti-clockwise rotation. The closed loop 39 also includes a rectilinear upstream portion 39C which is arranged tangentially to the drive wheel 60 upstream of the turning portion 39A in the direction of anti-clockwise rotation.

The conveyor 36 is capable of successively transporting each preform 12 carried by a gripping member 38 from the loading point "P1" at which the preform 12 is taken by the gripping member 38, to an unloading point " P2” at which the preform 12 is released from the gripping member 38. From the unloading point “P2” to the loading point “P1”, the gripping members 38 move empty.

The manufacturing installation 10 includes means for distributing the preforms 12 which are intended to convey the preforms 12 one after the other to the conveyor 36.

The distribution means here comprise a horizontal input transfer wheel 62 which is mounted to rotate around its central vertical axis "E".

The input transfer wheel 62 comprises at its periphery means for individually receiving each preform 12, formed here by notches 64 for receiving the necks 16 of the preforms 12. The notches 64 are mutually spaced circumferentially with pitch "S". These notches 64 are able to receive the necks 16 of the preforms 12 and to support the preforms 12 thanks to their projecting collar 22 which is supported on the periphery of the notches 64 by their support surface 20.

The notches 64 of the input transfer wheel 62 are here arranged at an altitude lower than that of the gripping members 38 of the conveyor 36.

As shown in , in plane projection, the input transfer wheel 62 is here arranged tangent to the turning portion 39A of the loop 39 closed at a first point of tangency "P3". The first point “P3” of tangency is arranged upstream of the loading point “P1”.

The input transfer wheel 62 is rotated around its axis "E" in a clockwise direction, referring to the . The speed of rotation of the input transfer wheel 62 is synchronized with the speed of rotation of the drive wheel 60 so that a gripping member 38 and a notch 64 of the input transfer wheel 62 are positioned present simultaneously at the first point of tangency "P3" directly above each other.

The drive wheel 60 also includes means intended to hold the preforms 12 during the dressing operation by the gripping members 38.

For this purpose, the drive wheel 60 comprises receiving means, such as transport forks 66 as shown in Figures 5 to 7. Each transport fork 66 delimits a housing of shape complementary to the shape of the neck 16 of each preform 12.

Each transport fork 66 here grips a preform 12 associated just below the collar 22.

The transport forks 66 are carried by the drive wheel 60. The transport forks 66 are thus driven by the drive wheel 60 along a circular path.

According to a not shown variant of the invention, the receiving means are pliers which have jaws which are articulated between a closed position and an open position, the jaws being elastically returned towards their closed position.

According to a not shown variant of the invention, the transport forks are carried by a plate with an axis coaxial with the axis "D" of the drive wheel 60.

The transport forks 66 are distributed over all the circumferences of the drive wheel 60, substantially at the same altitude as the notches 64 of the input transfer wheel 62. The transport forks 66 are spaced circumferentially from each other by the predetermined pitch "S" so that a transport fork 66 is arranged vertically under each gripping member 38.

Thus, in plane projection the circular trajectory of the transport forks 66 is superimposed on the trajectory of the gripping members throughout the turning portion 39A. In other words, in plane projection, the trajectory of the gripping members 38 coincides with the trajectory of the transport forks 66 throughout the bend portion 39A. In addition, each transport fork 66 moves vertically in coincidence with an associated gripping member 38 of the conveyor 36.

As shown in , each transport fork 66 is intended to grip a preform 12 just below the collar 22 so as to extract the preform 12 from the input transfer wheel 62 and to support it during the dressing operation.

The transport fork 66 grips the preform 12 below the flange 22 so that the supporting surface 20 of the flange 22 rests on an upper face, called the reaction face 68, of the transport fork 66. The reaction face 68 is thus in contact with the collar 22. The reaction face 68 is turned towards the rim 26 of the neck 16, here towards the top. When the preform 12 is gripped by the transport fork 66, its tamper-evident groove 30 is left free. The transport fork 66 supports the preform 12, but it does not limit its vertical movement upwards.

As will be explained subsequently, during the dressing operation, the preform 12 is transported by the transport fork 66 until it fits with the gripping member 38.

The invention proposes a method of transferring the preform 12 onto the conveyor 36 in which, during the dressing operation, the neck 16 of the preform 12 is clamped vertically between the reaction face 68 of the transport fork 66 and a holding face 70 vertically opposite the reaction face 68, the holding face 70 being supported against the rim 26. Thus, the vertical upward movement of the preform 12 is intended to be limited only by contact of the rim 26 with the holding face 70 vertically opposite the reaction face 68. This makes it possible to correctly maintain the preform 12 during the dressing operation while leaving the tamper-evident groove 30 of the neck 16 free.

In a non-limiting manner, the holding face 70 is here formed by the contact face 50 of the ejection member 48. During the dressing operation, the ejection member 48 is therefore controlled to slide so as to tighten the neck 16 against the transport fork 66.

According to another aspect of the invention, the operation of covering the preform 12 by the gripping member 38 requires a vertical sliding movement of the preform 12 in a nesting position relative to the gripping member 38 . Indeed, in the embodiment shown in the figures, the gripping members 38 are not mounted to slide vertically relative to the drive wheel 60.

According to the teachings of the invention, the transport forks 66 are advantageously mounted to slide vertically relative to the drive wheel 60 between a low transfer position in which the transport fork 66 is arranged at the same altitude as the notches 64 of the input transfer wheel 62, as illustrated in Figures 11, 13 and 23 and a high nesting position in which the neck 16 of the preform 12 carried by the transport fork 66 is at the same altitude as members 38 gripping member 38 is fitted vertically into the neck 16, as illustrated in and 23.

Thus, according to the embodiment shown in , the transport forks 66 are mounted sliding vertically on the drive wheel 60, while the gripping members 38 remain fixed in a vertical direction relative to the drive wheel 60. Thus, it is the transport forks 66 which vertically lift the preforms 12 in order to fit them with the gripping members 38 during the dressing operation.

As shown in , the movements of the transport forks 66 and/or ejection members 48 are here controlled by cams.

In a variant not shown, the movements of the transport forks and/or cams are controlled by pneumatic cylinders or electric motors.

As shown in Figures 5 and 6, each transport fork 66 is attached to an associated carriage 72. The carriage 72 is mounted sliding vertically on the drive wheel 60 via a slide 73 fixedly mounted on the drive wheel 60. A cam follower 74 is here formed by a roller which is rotatably mounted at a free lower end of the carriage 72 of each transport fork 66.

The cam follower 74 is intended to cooperate with a cam path 76 which is here formed by the lower surface of a cladding rail 78 fixed relative to the ground. The clothing rail 78 is fixed relative to a frame on which the drive wheel 60 is rotatably mounted. The rail 78 is shown in more detail in a view developed in the . The direction of movement of the gripping member 38 is indicated by the arrow “F1”.

Referring again to the , each transport fork 66 is elastically returned to its high nesting position by a return spring 80 which is interposed between an integral moving face of the carriage 72, here located at an upper end of the spring 80, and a fixed face of the drive wheel 60, here located at an upper end of the slide 73.

In the event of a malfunction in which the spring 80 is not sufficiently responsive, a counterrail 82 is provided opposite the clothing rail 78 and cooperating with the cam follower 74 to push the transport fork 66, for example. via the carriage 72, towards its nesting position.

As shown in Figures 5 to 7, the device further comprises a sliding control mechanism of the face 70 for holding relative to the transport fork 66 which is mounted on the carriage 72.

The control mechanism here comprises a second control fork 84 which is intended to be received around the ejection member 48, to the right of a drive face 87 facing upwards throughout the portion 39A of turn. The control fork 84 is intended to press the drive face 87 downwards as will be explained subsequently.

In the embodiment shown in the figures, the control fork 84 is here received in an external groove 85 of the ejection member 48, the drive face 87 forming a lower face of the groove 85. Thus, the fork 84 of control is engaged with the ejection member 48 between an engagement point “P6” located at an upstream end of the turning portion 39A and a release point “P5” located at a downstream end of the portion 39A of turn, as shown in . The control fork 84 is thus temporarily integral in vertical sliding with the ejection member 48 when the ejection member 48 circulates along the turning portion 39A.

The groove 85 is delimited vertically by two horizontal faces. The groove 85 has a height slightly greater than the thickness of the control fork 84 so that the control fork 84 is received in the groove 85 with vertical clearance. This clearance makes it easier to insert and remove the control fork 84 relative to the groove 85.

The control fork 84 is arranged vertically above and at a distance from the transport fork 66. The control fork 84 is more particularly arranged above the carriage 72.

The control fork 84 is slidably mounted in the carriage 72 between a lower clamping position, illustrated in Figures 13 and 23, and an upper release position, illustrated in Figures 11, 15, 17 and 21. The control fork 84 is thus controlled between its lower clamping position, in which it urges the drive face 87 to press the ejection member 48 against the rim 26, and its upper release position relative to the transport fork 66, in which the fork is spaced vertically from the transport fork 66 to stop pressing the ejection member 48 against the rim 26.

In the lower clamping position, the fork 84 controls the ejection member 48 in a clamping position of the neck 16 of the preform 12 carried by the transport fork 66 in which the face 70 for holding the member 48 of ejection is supported against the rim 26 so as to tighten the support surface 20 of the collar 22 against the reaction face 68 of the transport fork 66.

In the upper release position, the control fork 84 is spaced vertically from the transport fork 66 so that the holding face 70 is no longer tight against the rim 26. The neck 16 of the preform 12 is thus no longer tight between the ejection member 48 and the transport fork 66.

The travel of the control fork 84 between these two positions relative to the carriage 72 is very significantly less than the sliding travel of the ejection member 48 between its extreme stripping position and its extreme dressing position. Thus, it is the combined sliding of the carriage 72 relative to the drive wheel 60, on the one hand, and of the control fork 84 relative to the carriage 72, on the other hand, which allows the fork 84 control to control the sliding of the ejection member 48 between its extreme undressing position and its extreme dressing position.

The control fork 84 being slidably mounted in the carriage 72, when the control fork 84 is immobilized in one of its positions relative to the carriage 72 and the control fork 84 is engaged with the ejection member 48, the sliding of the transport fork 66 jointly causes the sliding of the holding face 70 so that the holding face 70 remains fixed relative to the transport fork 66 during its sliding.

As shown in , the control fork 84 is here guided in sliding between its two positions in the carriage 72 by a rod 86 which extends vertically downwards. The rod 86 is received in a vertical axis guiding orifice 88 of the carriage 72.

The control fork 84 is here controlled in sliding by a first cam system which is used when the transport fork 66 occupies its transfer position. For example, a cam follower 90 is here formed by a roller which is mounted at a lower end of the rod 86 projecting through a lower end of the guide orifice 88 below the carriage 72.

The cam follower 90 is intended to cooperate with a cam path 92 of a control rail 94 fixed relative to the ground to push the control fork 84, and therefore the holding face 70, towards its dressing position, as represented at the .

The control fork 84 is here elastically returned to its release position by an elastic return member 96, such as a spring, which is interposed between a fixed face relative to the carriage 72 and a fixed face relative to the fork 84 control. The fixed face relative to the carriage 72 is here arranged above the fixed face relative to the control fork 84 and the elastic return member 96 works in compression.

In the embodiment shown in , the carriage 72 comprises a vertical column 98 which projects above the carriage 72 and on which a body of the control fork 84 is mounted sliding vertically. The elastic return member 96 is arranged around the column 98 and it is interposed between a head of the column 98, forming the fixed face relative to the carriage 72, and an upper face of the body of the control fork 84, forming the fixed face relative to the control fork 84.

The elastic return member 96 exerts a force greater than the force exerted by the elastic return means 58 of the ejection member 48. More particularly, the stiffness of the return member 96 is here greater than the stiffness of the elastic return means 58 of the ejection member 48. Thus, when the control fork 84 engages with the ejection member 48, the elastic return means 58 does not exert sufficient force to return the ejection member 48 to its extreme dressing position.

The control fork 84 is also capable of being controlled towards its release position by a second cam system which acts when the transport fork 66 occupies its nesting position. In the embodiment shown in , this second cam system comprises a lever 100 oriented generally radially relative to the axis of the drive wheel 60. The lever 100 is pivotally mounted around a central axis “G” tangent to the direction of rotation of the drive wheel 60.

The lever 100 has two free ends here provided with rollers 102, 104. The first roller 102 is arranged at a distal end of the lever 100 relative to the control fork 84. It is intended to come into contact with a face 106 of the drive wheel 60 when the transport fork 66 occupies its nesting position, as shown in . During this contact the distal end of the lever 100 is pushed downwards, causing the tilting of the lever 100 and the lifting of the second roller 104 arranged at the end of the lever 100 proximal to the control fork 84. The second roller 104 then comes into contact with a fixed lower face relative to the control fork 84. This thus causes the control fork 84 to rise upwards.

Referring again to the , the preforms 12 are here distributed in a line at the entrance to the manufacturing installation 10 by a slide 108 in which the preforms 12 slide while pushing towards a downstream end. Each preform 12 is then loaded onto a horizontal entry wheel 110 having notches 112 at its periphery. Each notch 112 carries a preform 12. Thus, the preforms 12 are spaced apart from the pitch “S” determined in the entry wheel 110. .

As shown in , each notch 112 of the input wheel 110 is delimited in top view by an edge in the form of an arc of a circle extending over an angle less than or equal to 180°. The imaginary line segment connecting the two ends of the arc of a circle is called the chord. The imaginary line intersecting the chord orthogonally in the middle in the horizontal plane is called the arrow “H”. To be able to efficiently load each preform 12 coming from the entry slide 108, the arrow “H” of each notch 112 is here oriented inclined at an angle “h” with respect to the direction “R” which is purely radial with respect to to the axis of rotation of the input wheel 110. Thus, a downstream edge of the notch 112, in the direction of rotation of the input wheel 110, projects radially relative to an upstream edge of the notch.

As shown in , the transport fork 66 has the same configuration as the notches 112 of the input wheel 110. When the transport forks 66 support the preforms 12, they are arranged at the same altitude as the notches 112 to be able to grasp each preform 12 under the collar 22. As a result, if the transport fork 66 came to grasp the preforms 12 directly on the input wheel 110, the downstream edge of the transport fork 66 would hit the downstream edge of the notch 112.

To solve this problem, the manufacturing installation 10 includes the input transfer wheel 62 which is arranged between the input wheel 110 and the conveyor 36. The notches 64 of the input transfer wheel 62 have the shape of an arc of a circle which extends over an angle less than 180° and whose arrow is directed purely radially relative to the axis of rotation of the input transfer wheel 62, as indicated by the right “R " of the . This makes it possible to avoid interference between the transport forks 66 and the input transfer wheel 62.

Due to this configuration of the notches 64 of the input transfer wheel 62, the path of the preforms 12 in the input transfer wheel 62 is bordered by a counterrail 114 fixed relative to the ground so as to maintain the preforms 12 in the notches 64, as shown in .

We now explain the operation of the installation during the operation of dressing the preforms 12 with reference to Figures 11 to 24.

As shown in , each transport fork 66 passes to the first point of tangency "P3" of the input transfer wheel 62 and the closed loop 39, at the same time as a notch 64 of the input transfer wheel 62 carrying a preform 12. The transport forks 66 being arranged substantially at the same altitude as the notch 64, the transport fork 66 is capable of gripping the preform 12 under the collar 22. The preform 12 is thus transferred from the transfer wheel 62 input on the drive wheel 60.

As shown in , to position the transport fork 66 at the correct altitude, the cam path 76 comprises a first descent slope 76A which is intended to control the descent of the transport fork 66 towards its low transfer position. This descent slope 76A is arranged upstream of the point “P3” of tangency. Thus, as illustrated in , at point “P3” of tangency, the transport fork 66 is already controlled by the cam path 76 in the transfer position against the elastic return force of the spring 80.

At point “P3” of tangency, the control fork 84 is already engaged with the ejection member 48. The sliding of the carriage 72 towards its low transfer position jointly drives the control fork 84 in sliding, causing the ejection member 48 to slide towards its extreme stripping position. However, at point “P3” of tangency, the ejection member 48 does not quite occupy its extreme stripping position. As shown in , the control fork 84 is in fact controlled in its upper release position so that the ejection member 48 is slightly raised above the level of the rim 26, under the effect of the means 58 for elastic return of the ejection member 48, to allow the transport fork 66 to take on board the preform 12 without the latter coming into contact with the ejection member 48. To enable the control fork 84 to be controlled in its release position, the cam path 92 of the control rail 94 comprises a rise ramp 92A (represented in Figure ) arranged downstream of the point “P3” of tangency, the cam path 92 maintaining the control fork 84 in its release position during the passage of the point “P3” of tangency, as shown in .

When the preform 12 is gripped by the transport fork 66, it thus occupies its transfer position in which the axis "A" of the preform 12 is coaxial with the axis of the gripping member 38, the member 38 gripping device being thus arranged opposite and at a distance from the neck 16 of the preform 12. The control fork 84 occupying its release position, the ejection member 48 does not interfere with the preform 12 during its transfer.

As shown in , the first point "P3" of tangency is arranged on the turning portion 39A of the closed loop 39, upstream of the loading point "P1" which is arranged on the turning portion 39A of the closed loop 39 downstream of the first point “P3” of tangency, for example at point “P5” of clearance located at the downstream end of the turn portion 39A. Thus, the dressing operation advantageously lasts as long as the transport fork 66 travels through an angular sector "P3-P1" of angle "α".

The trajectory of the preform 12 carried by the transport fork 66 and that of the gripping member 38 are superimposed along the angular sector "P3-P1" which forms, in plane projection, a first line of intersection between the trajectory of the gripping members 38 and that of the transport forks 66.

Thus, between the first point "P3" of tangency and the loading point "P1", the preform 12 is carried by the transport fork 66.

As shown in Figures 15 and 16, the cam path 76 also includes a second downstream slope 76B which is intended to control the rise of the transport fork 66 towards its nesting position. At least a portion of the counterrail 82 is more particularly facing the downstream slope 76B to guarantee that the transport fork 66 is controlled towards its nesting position even in the case where the return spring 80 is not not able to effectively return the transport fork 66 to its nesting position.

The second downstream slope 76B extends here over at least part of the turning portion 39A corresponding to the angular sector of angle "α", so that the dressing operation can be carried out for a sufficiently long duration to ensure a reliable fitting of the gripping member 38 into the neck 16 of the preform 12.

However, before the transport fork 66 begins to slide towards its nesting position, the ejection member 48 is controlled in its extreme stripping position as illustrated in Figures 13 and 14. For this purpose, the control fork 84 is controlled towards its clamping position. This ensures that the preform 12 is well maintained coaxially with the gripping member 38 during the dressing operation.

In the example shown in the figures, the control fork 84 is controlled towards its clamping position by a downstream downward slope 92B of the cam path 92 of the control rail 94. This downward slope 92B is arranged upstream of the upward slope 76B of the rail 78. Thus, the elastic return member 96 makes it possible to elastically return the control fork 84 towards its clamping position, against the force of weaker elastic return exerted by the elastic return means 58.

Throughout the dressing operation illustrated in Figures 13 to 16, the control fork 84 is held in its clamping position by the elastic return member 96.

At the end of the dressing operation, as illustrated in , the preform 12 is integral in movement with the gripping member 38 and the ejection member 48 occupies its extreme dressing position.

Furthermore, at the exit of the turning portion 39A, the control fork 84 is intended to be released from the groove 85 of the ejection member 48. Likewise, the preform 12 is intended to be separated from the transport fork 66 to allow the preform to continue its movement along the loop 39 closed with the gripping member 38 while the transport fork 66 continues its trajectory circular. If the neck 16 of the preform 12 remained tight between the transport fork 66 and the control fork 84, this would cause friction with the preform 12 and with the drive face 87 during their separation. Thus, not only is maintaining the preform 12 no longer useful but it is also not desired.

Thus, at the end of the dressing operation and before the gripping member 38 reaches the release point “P5”, the control fork 84 is moved away from the drive face 87.

In the example shown in the figures, this is achieved by means of the control fork 84 which is here automatically controlled in its release position when the carriage 72 reaches its nesting position to allow the ejection member 48 to no longer be requested by the control fork 84. The control fork 84 is here slid vertically upwards in the groove 85, thanks to the vertical play, while the ejection member 48 remains in its extreme dressing position. The control fork 84 is thus moved away from the drive face 87 of the ejection member 48.

The carriage 72 being in the high position, the control fork 84 is controlled towards its release position by contact between the roller 102 at the distal end of the lever 100 and the face 106 facing the drive wheel 60 when the transport fork 66 completes its movement towards its nesting position.

As shown in Figures 17 and 18, before the gripping member 38 reaches the release point "P5", the transport fork 66 is also moved away from the collar 22. The preform 12 is in fact entirely carried by the gripping member 38. The transport fork 66 is thus controlled in an intermediate position, slightly below its nesting position. The travel of the transport fork 66 between its nesting position and its intermediate position is less than the vertical clearance between the drive face 87 of the ejection member 48 and the control fork 84. Thus, even in the intermediate position of the transport fork 66, the control fork 84 is not in contact with the drive face 87.

In the embodiment shown in , this is achieved by means of a slight downward slope 76C of the cam path 76 which is arranged downstream of the upward slope 76B. Thus, when the gripping member 38 arrives at the release point “P5”, the preform 12 is no longer in contact with the transport fork 66 at all, which avoids unwanted friction.

As illustrated in Figures 19 and 20, during their circulation along their circular trajectory from the point “P5” of clearance of the turn portion 39A to the point “P6” of engagement of the turn portion 39A, the transport forks 66 are held in their nesting position by the return spring 80 and the control forks 84 are held in their release position against the elastic return force of the elastic return member 96 by the lever 100 in contact with the face 106 of the drive wheel 60.

Just before arriving at the engagement point “P6” located at the upstream end of the turn portion 39A, the transport fork 66 is again controlled towards its intermediate position by means of a slight downward slope 76D arranged at a downstream end of cam path 76, as illustrated in .

Thus, when the transport fork 66 arrives at the engagement point "P6", it again engages with a preform 12 carried by a gripping member 38, in particular after heating the body 14 of the preform 12, as illustrated to the . The control fork 84 then engages with the ejection member 48 associated with said gripping member 38. At this point “P6” of engagement, the transport fork 66 is still located slightly below the collar 22 without touching it. Likewise, the control fork 84 occupying its release position, the latter is engaged in the groove 85 of the ejection member 48 without being in contact with its drive face 87.

As shown in , the installation 10 also includes an output transfer wheel 116.

The output transfer wheel 116 is arranged substantially at the same altitude as the input transfer wheel 62. It comprises articulated arms each equipped at its end with a clamp 118 for gripping a preform 12 by its neck 16. The output transfer wheel 116 is mounted to rotate in a clockwise direction around an axis "F" . The grippers 118 move along a closed loop trajectory which is tangent to the circular trajectory of the transport forks 66 at a second tangency point "P4".

The speed of rotation of the output transfer wheel 116 is synchronized with the speed of rotation of the drive wheel 60 so that a clamp 118 of the output transfer wheel 116 passes simultaneously with a transport fork 66 at the second point “P4” of tangency which is arranged downstream of the point “P2” of engagement.

In plane projection, the trajectory of the transport forks 66 and the trajectory of the gripping members 38 are superimposed between the engagement point "P6" and the second tangency point "P4".

The second point "P4" of tangency is more particularly arranged upstream of the first point "P3" of tangency with respect to the direction of rotation of the drive wheel 60.

Thus between the moment at which the preform 12 is gripped at the engagement point "P2" by a transport fork 66 and the moment at which the preform is transferred to the exit transfer wheel 116 at the second point "P4" of tangency, the preform 12 is engaged with the transport fork 66 to the right of the associated gripping member 38.

During a stripping operation from the engagement point “P6” to the second unloading point “P2”, the preform 12 is disengaged from the gripping member 38 by a progressive vertical sliding movement towards the bottom of the carriage 72 which begins after the engagement point "P6" and which ends substantially at the unloading point "P2", as illustrated in Figures 23 and 24. This downward sliding movement is controlled by the descent slope 76A of the rail 78 which is arranged between the engagement point “P6” and the unloading point “P2”. In this movement, the carriage 72 drives the control fork 84 downwards. Due to this sliding, the lever 100 is no longer in contact with the face 106 of the drive wheel 60, which has the effect of elastically returning the control fork 84 to its clamping position by the member 96 elastic return, such as a spring.

The control fork 84 being engaged with the ejection member 48, the sliding of the control fork 84 together with the carriage 72 causes the ejection member 48 to slide towards its extreme stripping position. This has the effect of dislodging the preform 12 from the gripping member 38. The collar 22 of the preform 12 is thus pushed into contact with the transport fork 66 by the ejection member 48.

During this stripping operation, the preform 12 is thus carried by the transport fork 66. The neck 16 is more particularly clamped between the face 70 for holding the ejection member 48, in contact with the rim 26, and the reaction face 68 of the transport fork 66, in contact with the surface 20 of support of the collar 22.

The transport fork 66 leaving the tamper-evident groove 30 of the preform 12 free, the gripper 118 of the output transfer wheel 116 grasps the preform 12 by its tamper-evident groove 30 at the second point “P4” of tangency.

This allows the clamp 118 to grip the preform in a stable manner without risking dropping the preform 12 or causing it to rotate randomly around its axis “A”. It is in fact preferable for the preform 12 to rotate as little as possible between its exit from the heating station 32 and its entry into the forming station 34, particularly when the body 14 of the preform 12 has been heated according to a determined heating profile. implying differentiated heating around its axis “A”.

It is preferable that the preform 12 is no longer in contact with the ejection member 48 when it passes the second point “P4” of tangency to prevent the neck 16 of the preform 12 from rubbing. For this purpose, the slope 92A of rise of the control rail 94 is arranged between the unloading point “P2” and the second point “P4” of tangency, after the transport fork 66 has reached its transfer position.

Thus, the same transport forks 66 are used successively to carry the preforms 12 during the dressing operation, then during the stripping operation.

The invention thus makes it possible to firmly hold the preforms 12 during dressing and undressing operations while allowing the heated preforms to be gripped safely and stably at the outlet of the heating station by means of pliers. This is further accomplished by reducing costs due to the use of the ejection member 48 to perform both the function of stabilizing the preform and the function of stripping the preform.

Claims (11)

Method for transferring containers, and in particular preforms (12) made of thermoplastic material, comprising a neck (16) having a main axis (A), opening through an opening (24) delimited by a free edge of the neck called "drinking (26) )", the container being transferred to a conveyor (36) in which the container is held by a gripping member (38) fitted axially with the neck (16) during a dressing operation,
characterized in that, during the dressing operation, the neck (16) is clamped axially between a reaction face (68) facing the rim (26) and a face (70) for maintaining axially facing screw of the reaction face (68), the holding face (70) resting against the rim (26). Method according to the preceding claim, characterized in that the reaction face (68) is in contact with a flange (22) of the neck (16). Method according to any one of the preceding claims, characterized in that each gripping member (38) of the conveyor (36) comprises an ejection member (48) mounted sliding axially on the gripping member (38) between a position extreme dressing allowing the axial interlocking of the gripping member (38) with the neck (16) and an extreme undressing position towards which the ejection member (48) is slid so that one face (50 ) contact of the ejection member (48) presses on the rim (26) of the neck (16) to disengage it entirely from the gripping member (38), the holding face (70) being formed by the contact face (50) of the ejection member (48). Device for implementing the method according to any one of the preceding claims, the device comprising:
- at least one fork (66) for transporting a container which moves in coincidence with an associated gripping member (38) of the conveyor (36), an upper face (68) of the transport fork (66) forming the reaction face (68);
- means of distribution (62) of the preforms (12) which comprise means of individual reception (64) of each container so as to successively lead each container to a point (P3) of tangency with the trajectory of the fork (66) transport to which the container is transferred to the transport fork (66);
- the transport fork (66) being mounted to slide axially between a transfer position in which the transport fork (66) is positioned at the same level as the individual receiving means (64) for gripping the neck (16) when the container is carried by the distribution means and a nesting position in which the neck (16) of a container carried by the transport fork (66) is intended to be nested with the gripping member (38);
characterized in that the device comprises a sliding control mechanism for the holding face (70) which is slidably mounted on a carriage (72) on which the associated transport fork (66) is fixed so that, when the mechanism control is immobilized relative to the carriage (72), the sliding of the transport fork (66) jointly causes the sliding of the holding face (70). Device according to the preceding claim taken in combination with claim 3, characterized in that the sliding stroke of the control mechanism relative to the carriage (72) is less than the sliding stroke of the ejection member (48) between its two extreme positions, the mechanism being controlled between a tightening position of the neck (16) in which it is brought closer to the transport fork (66) to urge the holding face (70) towards the reaction face (68) and a position for releasing the neck (16) in which it is moved away from the transport fork (66) so as to no longer stress the face (70) for holding it tight against the rim (26). Device according to any one of Claims 4 or 5, characterized in that the transport fork (66) is controlled in sliding by a cam path (76) fixed relative to the ground which cooperates with a cam follower (74). which is carried by the carriage (72). Device according to any one of claims 4 to 6, characterized in that the transport fork (66) is elastically returned to its upper nesting position. Device according to any one of claims 4 to 7, characterized in that the sliding control mechanism of the holding face (70) comprises a cam follower (90) which is mounted sliding axially in the carriage (72), and which cooperates with a cam path (92) fixed relative to the ground. Device according to the preceding claim, characterized in that the sliding control mechanism of the holding face (70) is elastically returned to its clamping position. Device according to any one of claims 4 to 9 taken in combination with claim 3, characterized in that the control mechanism comprises a control fork (84) slidably mounted in the carriage (72) and which cooperates with a face ( 87) of the ejection member (48) to urge the ejection member (48) downwards. Device according to any one of claims 4 to 10, characterized in that the device comprises a plurality of transport forks (66) mounted integrally in rotation with a drive wheel (60) around which the members (38) of gripping are indexed during their movement, each carriage (72) being mounted sliding axially on the drive wheel (60).