FR3102761A1 - Accumulation circuit for aligned and straightened preforms - Google Patents

Abstract

The invention relates to a circuit (30) for accumulating aligned and straightened preforms (26), in particular preforms (26) made of thermoplastic material, in an accumulation line (38) comprising at least two conveyors (40A, 40B). rectilinear accumulation arranged in series each comprising: - a sliding track (42) intended to guide the preforms (26) along a rectilinear path (R1, R2); - preform drive units (26); characterized in that it comprises an intermediate accumulation conveyor (48) interposed between the upstream rectilinear conveyor (40A) and the downstream rectilinear conveyor (40B), comprising: - a track (50) for sliding the preforms (26) along of a path (C) in the form of an arc of a circle, the sliding track (50) being delimited by a fixed rail (54) in the form of a circular arc and by a second rotating annular rail (56). Figure for abstract: Figure 2

Description

Accumulation circuit for aligned and straightened preforms

Technical field of the invention

The invention proposes an accumulation circuit for aligned and straightened preforms, in particular preforms made of thermoplastic material, in an accumulation line comprising at least two rectilinear accumulation conveyors arranged in series, each comprising:

- a sliding track delimited by a pair of rectilinear rails intended to receive the preforms in suspension and to guide them in sliding along a rectilinear path;

- preform drive members downstream of the sliding track.

Technical background

The accumulation conveyor is intended to be implemented in an installation for the manufacture of containers made of thermoplastic material and in particular of polyethylene terephthalate (PET) by forming, in particular by blow molding or stretch-blow molding, of preforms. Such an installation makes it possible to produce containers in very large series at very high rates, for example greater than 85,000 bottles per hour.

According to a well-known technique, such containers are produced in two main steps.

In a first step, injection molding of a PET preform is carried out. This preform comprises a substantially tubular body which is closed at one of its axial ends, the opposite end being open via a neck. The neck has, from this injection molding operation, the final shape of the neck of the container. Generally, the neck of the container has a thread.

In a second forming step, the hot preforms are housed in the mold cavities. Then, a pressurized forming fluid is injected into the preforms to press the wall of the preform against the walls of the cavity to shape the preform into the final container. This blowing operation is generally accompanied by a stretching operation consisting in introducing an elongation rod into the preform through its body in order to axially stretch the wall of the preform.

The preform generally comprises an annular support face which projects radially outwards with respect to the rest of the body and which is oriented axially towards the closed end of the body. Such a support face is, for example, carried by an annular support collar which extends radially projecting outwards relative to the rest of the preform and which is arranged at the base of the neck.

There are installations in which the preforms, once injected, are directly transmitted to the forming station, each preform being transported individually.

However, in many cases, the preforms are made by injection at a first location and are blow molded to the final shape of the container at a second location on a specific manufacturing facility. Such technology makes it possible to carry out the blow molding operation as close as possible to the place of bottling, the injection operation being able to be carried out at any place. Indeed, it is relatively easy and inexpensive to transport preforms of reduced size, while transporting containers after blow molding has the disadvantage of being economically unprofitable due to their very large volume.

In the case where the injection station and the manufacturing installation by forming are two totally independent machines, the preforms are generally delivered in bulk. The manufacturing installation therefore has a device for aligning the preforms in one file and straightening them. Such a manufacturing installation also comprises at least one heating station and one station for blowing the containers from the hot preforms.

The present invention relates more particularly to a device for aligning and straightening preforms in which the preforms are not indexed in position. However, most of the time, the preforms come out in trains of tight preforms, each preform being in contact with the following preform.

From the entrance to the heating station to the exit from the forming station, the preforms are picked up individually by gripping means (such as spinners or grippers). The preforms are thus moved individually in line along a production path.

The start of the forming cycle, which must produce containers at a rate of several tens of thousands of units per hour, is not dependent on the presence of preforms in the associated molds, so that in absence of one or more preform(s) in the flow of preforms, the forming unit runs empty in the mold(s) supposed to accommodate this (these) preform(s). This results in wasted energy and decreased productivity.

However, it happens that the preforms are not in contact with each other on leaving the alignment and straightening device. A hole is then created between two trains of preforms which is liable to disturb the supply of the following stations. Places are thus found vacant in the following conveyors. The yield of the manufacturing installation is then likely to drop.

To avoid this phenomenon, it is known to arrange an accumulation conveyor between the alignment and straightening device and the first preform processing station. Such a conveyor makes it possible to accumulate preforms in an accumulation queue, the preforms being distributed one by one to the next station, for example to a notched wheel. Such an accumulation queue leaves time to fill any holes between trains of preforms leaving the alignment and straightening device by distributing preforms already stored in the accumulation queue. The length of the accumulation queue is thus temporarily reduced until the arrival of the late train of preforms.

The accumulation queue must contain a minimum number of preforms adapted to the rate of the receptacle manufacturing installation to prevent the accumulation queue from being emptied too quickly during a temporary blockage.

For the distribution of the preforms from the accumulation queue to the next station, a retractable blocking finger is provided, for example at the end of the accumulation conveyor, which is controlled between a position blocking the sliding of the preforms and a retracted release position. the sliding of the preforms so as to distribute the preforms at a determined rate to the following conveyor so that each place of the following conveyor is loaded with an associated preform. The preforms waiting in the accumulation queue thus pass at a distribution speed corresponding to said rate.

To make it possible to make up for the holes between trains of preforms, the accumulation conveyor advantageously makes it possible to advance the preforms as far as the accumulation queue at a free displacement speed greater than the distribution speed of the accumulation queue. The length of the accumulation queue is for example regulated by controlling the flow rate of the alignment and straightening device.

Such an accumulation conveyor mainly comprises a sliding track which is delimited by two support rails on which the preform is received in support by its flange, the body of the preform hanging between the rails. Devices are also provided for driving all the preforms over the entire length of the accumulation conveyor. Indeed, in the absence of such drive members, the preforms passively pushed by the pressure of preforms upstream of the line run the risk of jamming between the guide rails, thus causing a plug.

It is for example known to arrange an accumulation conveyor of the type called "gravity rail". In such an accumulation conveyor, the rails are arranged on a slope from an upper entry end of the preforms to a lower exit end. The inlet end is arranged higher than the outlet end to allow the preforms to slide freely along the rails by gravity towards the outlet end. Under the effect of gravity, the preforms thus slide rapidly at the speed of free movement towards the outlet end as far as an accumulation queue. The preforms in the accumulation queue then advance more slowly, still under the effect of gravity, towards the end in the accumulation queue, at the dispensing speed.

However, such an accumulation conveyor is extremely bulky both in height and in length.

It is also known to use accumulation conveyors called "brush conveyors" which make it possible to enormously reduce the vertical bulk compared to a gravity rail conveyor.

An example of an installation 10 for the manufacture of containers of the state of the art has been shown, incorporating two brush conveyors 12 in FIG. 1. The installation 10 comprises in particular a device 11 for aligning and straightening preforms and a heating station 13 comprising a wheel 15 with notches which receives preforms 17 at the outlet of the accumulation queue.

As shown in Figure 1, such brush conveyors 12 comprise rectilinear guide rails 14 between which the preforms 17 are slidably received. Endless belts 16 equipped with brushes are arranged on either side of a rectilinear path 18 of the preforms 17. The path 18 of the body of the preforms 17 along the rails 14 is thus bordered by a stretched strand of each of the belts 16. The bristles (not shown) of the brushes come to rub against the body of the preforms 17 to push them towards a downstream exit end of the rails 14 in the direction indicated by the arrow "F0" of FIG. 1. A preform 17 is thus quickly pushed towards the downstream end of the outlet by the brushes until it reaches a queue 20 of accumulation.

When it has reached the accumulation queue 20, the preform 17 then advances more gently at the dispensing speed towards a downstream end 22 of the outlet in the accumulation queue 20, still under the effect of friction with the bristles of the brushes. The distribution speed of the preforms 17 of the queue 20 of accumulation is generally lower than their free movement speed. As a result, the brushes scroll faster than the preforms 17 which are part of the line 20 of accumulation. The flexibility of the bristles of the brushes makes it possible to avoid jamming of the belts or damage to the preforms. Indeed, the bristles of the brushes are deformed when they come into contact with a slower preform 17, which makes it possible to maintain a force for pushing the preforms towards the end 22 downstream of the outlet without damaging the preforms 17 or blocking the conveyor. 12 with accumulation.

However, the rails 14 must be straight in order to be able to cooperate with the brushes carried by the taut strands of the belts. When the operating rate of the manufacturing installation is high, it is necessary to provide a very long accumulation line.

In this respect, it is known to arrange several conveyors in series, for example two brush conveyors 12 as shown in FIG. 1, in order to achieve a sufficient accumulation queue length. The two conveyors are arranged in the extension of one another so that the preforms move on the rectilinear path 18 from their exit from the alignment and straightening device 11 to the heating station 13 . In other words, the angle formed between the rectilinear path 18 of the upstream brush conveyor 12 and the path 18 of the downstream brush conveyor 12 is 180°. Such a rectilinear circuit can be several meters long. Such an accumulation circuit therefore remains particularly cumbersome in the running direction of the preforms.

The invention proposes an accumulation circuit for aligned and straightened preforms, in particular preforms made of thermoplastic material, in an accumulation line comprising at least two rectilinear accumulation conveyors arranged in series, each comprising:

- a sliding track delimited by a pair of rectilinear rails intended to receive the preforms in suspension and to guide them in sliding along a rectilinear path;

- preform drive units downstream of the sliding track;

characterized in that it comprises an intermediate accumulation conveyor which is interposed between the upstream rectilinear conveyor and the downstream rectilinear conveyor, the intermediate conveyor comprising:

- a sliding track for the preforms along an arcuate path in the shape of an arc of a circle, the sliding track being delimited by a first fixed rail in the shape of an arc of a circle and by a second annular rotating rail, the rail revolving being rotated about a central axis which is arranged at the center of the circular arc;

- an upstream inlet end of the sliding track being connected to a downstream end of the sliding track of the upstream rectilinear conveyor;

- A downstream output end of the sliding track being connected to an upstream end of the sliding track of the downstream rectilinear conveyor.

According to other features of the invention:

- the rectilinear path of the upstream rectilinear conveyor forms with the rectilinear path of the downstream rectilinear conveyor an angle different from 180°;

- the rectilinear path of the upstream rectilinear conveyor forms with the rectilinear path of the downstream rectilinear conveyor an angle less than or equal to 90°;

- the rectilinear path of the upstream rectilinear conveyor forms with the rectilinear path of the downstream rectilinear conveyor an angle of 0° so that said rectilinear paths are parallel;

- the rectilinear path of the upstream rectilinear conveyor forms with the rectilinear path of the downstream rectilinear conveyor an angle greater than 90°;

- at least one of the rectilinear conveyors is formed by a brush conveyor whose drive members are formed by at least one endless circulating element, an outer face of which carries a series of brushes intended to come into contact with the preforms in suspension to drag them downstream along the sliding track;

- at least one of the rectilinear conveyors is a pneumatic conveyor which comprises blowing nozzles distributed along the conveying path which are capable of emitting a jet of gas in the direction of movement of the preforms to push them along the rectilinear path ;

- the intermediate conveyor comprises additional means for pushing the preforms towards the downstream exit end of the sliding track;

- the intermediate conveyor comprises friction elements which are intended to be in contact with the preforms and which are driven in rotation around the central axis together with the rotating rail to push the preforms towards the downstream outlet end by friction;

- the rotating rail and the friction elements are carried by a common wheel;

- at least in part, the friction elements are formed by brush bristles which extend radially projecting from the rotating rail;

- at least in part, the friction elements are formed by strips of elastomeric material which extend radially projecting from the rotating rail;

- the intermediate conveyor comprises a ramp of nozzles arranged along the arcuate path of the preforms, the nozzles being able to emit a jet of gas towards the preforms to push them towards the downstream outlet end.

Brief description of figures

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

FIG. 1 is a schematic top view which represents a receptacle manufacturing installation which is equipped with an accumulation circuit produced according to the state of the art in which two rectilinear accumulation conveyors are arranged in series;

FIG. 2 is a schematic top view which represents a receptacle manufacturing installation which is equipped with an accumulation circuit comprising a bend, here at 90°, produced according to the teachings of the invention;

Figure 3 is a schematic side view which shows a preform capable of being conveyed in the accumulation circuit of Figure 2;

FIG. 4 is a schematic top view showing a rectilinear conveyor downstream of the accumulation circuit of FIG. 2;

Figure 5 is a sectional view along the cross-sectional plane 5-5 of Figure 4 which shows a preform received in the rectilinear conveyor of Figure 4;

Figure 6 is a view similar to that of Figure 3 which shows an alternative embodiment of the accumulation circuit which here has a hairpin bend;

Figure 7 is a view similar to that of Figure 3 which shows an alternative embodiment of the accumulation circuit which here has a bend at an obtuse angle;

FIG. 8 is a detail view on a larger scale which schematically represents an intermediate conveyor of the accumulation circuit of FIG. 2 in which the bend is made;

Figure 9 is a cross-sectional view according to section plane 9-9 of Figure 8 which shows a preform received in the intermediate conveyor which is produced according to a first embodiment of the invention;

Figure 10 is a bottom view showing a wheel of the intermediate conveyor of Figure 8;

Figure 11 is a view similar to that of Figure 9 which shows the intermediate conveyor made according to a variant embodiment of the first embodiment of the invention;

Figure 12 is a bottom view showing a wheel of the intermediate conveyor of Figure 11;

Figure 13 is a sectional view along the section plane 13-13 of Figure 14 which shows a preform received in an intermediate conveyor made according to a second embodiment;

FIG. 14 is a top view showing the intermediate conveyor made according to the second embodiment of the invention;

Figure 15 is a view similar to that of Figure 13 which shows the intermediate conveyor made according to a third embodiment;

FIG. 16 is a top view showing a rectilinear conveyor upstream of the accumulation circuit of FIG. 2 produced according to a variant of the invention;

Figure 17 is a longitudinal sectional view along section plane 17-17 of Figure 16.

Detailed description of the invention

In the remainder of the description, elements having an identical structure or analogous functions will be designated by the same references.

In the rest of the description, the scrolling of the preforms 26 in the manufacturing installation 24 takes place from upstream to downstream.

In the rest of the description, the following local orientations will be adopted, without limitation, for each preform present in an intermediate accumulation conveyor 48 produced according to the teachings of the invention:

- longitudinal "L" directed from upstream to downstream according to the direction of movement of the preforms;

- transverse "T" which is orthogonal to the longitudinal direction "L" and which extends in the plane of the guide rails;

- vertical "V" directed from bottom to top according to the opposite direction of the earth's gravity.

There is shown schematically in Figure 2 part of an installation 24 for manufacturing containers of thermoplastic material by forming, in particular by blow molding or by stretch-blow molding. The manufacturing installation 24 here comprises a device 25 for aligning and straightening preforms 26 intended to supply a heating station 28 . The heating station 28 includes a transfer wheel 29 which includes individual receiving members for each preform 26. The receiving members are here formed by notches 31 which are distributed around the periphery of the transfer wheel 29 . An accumulation circuit 30 produced according to the teachings of the invention is inserted between the output of the alignment and straightening device 25 and the transfer wheel 29 of the heating station 28 .

An example of a preform 26 intended to be used with the alignment and straightening device 25 is illustrated in FIG. 3. Such a preform 26 is made of thermoplastic material, here PET. It is conventionally obtained by injection molding. It has a substantially axisymmetric shape around a main axis "A" shown vertically in Figure 3.

It comprises a body 33 in the form of an elongated tube along the main axis "A" having a closed axial end and which has at its opposite end, shown at the top in FIG. 2, a neck 32 that is axially open.

The preform 26 also includes an annular support collar 34 which projects radially with respect to the rest of the body 33, and which is arranged above a center "G" of gravity of the preform 26. The term "annular" means that the flange 34 goes around the preform 26 either continuously or discontinuously. In the latter case, the annular face is for example formed of separate segments which go around the preform 26 which are nevertheless sufficiently close together so that the preform 26 can be supported between two diametrically opposed supports whatever the position of the preform 26 around its main axis.

In the example shown, collar 34 is arranged at the base of neck 32, at the junction with body 33. The underside of collar 34 thus forms a support face.

As a variant, the collar can be arranged elsewhere than at the base of the neck, for example at the level of the rim.

The collar 34 is here made in one piece with the preform 26, but as a variant, the collar 34 can also be attached to the preform, for example by means of a cap.

The external diameter "D1" of the collar 34 is greater than the external diameter "D2" of the body 33 located directly under the collar and subsequently called "diameter "D2" under the collar".

The neck 32 has its final shape, while the body 33 is intended to be stretched during a subsequent forming operation to form the body 33 of the finished container. For this purpose, the installation 24 is equipped with a heating station 28 which is arranged downstream of the alignment and straightening device 25, as shown in FIG. 2.

Furthermore, the weight of the body 33 of the preforms 26 used is greater than the weight of the neck 32, including that of the collar 34. Thus, the center "G" of gravity of the preform 26 is located under the collar 34 with reference to the FIG. 3. Thus, a preform 26 supported by its collar 34 while resting on two diametrically opposite supports will naturally orient itself by gravity, neck 32 at the top.

The example shown in Figure 3 is non-limiting. It will be understood that the invention is intended to be applied to any type of preforms 26 having a flange 34 projecting radially with respect to the rest of the body 33, and having a center of gravity offset axially towards the body 33 with respect to said flange 34 .

In general, the preforms 26 are delivered in bulk to the inlet of the alignment and straightening device 25 from which they emerge aligned and straightened in a row via an outlet 36. an alignment and straightening device 25 as described in document WO 2016/166446 A1.

Due to various blockages that may occur in all types of alignment and straightening device, the preforms 26 do not come out of the alignment and straightening device 25 in a constant manner. Thus, the line of outgoing preforms 26 is likely to have "holes" separating two trains of preforms 26 at the places where the preforms 26 have been temporarily blocked. However, the heating station 28 requires a regular and constant supply of preforms 26. It is therefore not possible to supply the heating station 28 directly. Provision is therefore made for the possibility of temporarily accumulating the preforms 26 in an accumulation queue 38 to allow the continuous and regular supply of the transfer wheel 29 of the next processing station, here the station 28 for heating, so that each notch 31 of the transfer wheel 29 is guaranteed to receive an associated preform 26.

For this reason, an accumulation circuit 30 as shown in FIG. 2 is interposed between the output 36 of the alignment and straightening device 25 and the heating station 28.

Such an accumulation circuit 30 is capable of rapidly conveying the preforms 26 downstream to the line 38 of accumulation of preforms.

As explained in the preamble, the preforms 26 of the queue 38 of accumulation advance at a distribution speed directly dependent on the rate of the conveyors of the following stations. Before reaching the accumulation queue 38, the preforms 26 pass through the accumulation circuit 30 at a speed called "free movement speed" which is greater than the distribution speed.

The circuit 30 for accumulating preforms 26 aligned and straightened in an accumulation line 38 comprises at least two rectilinear accumulation conveyors 40A, 40B which are arranged in series which will subsequently be called upstream rectilinear conveyor 40A and downstream rectilinear conveyor 40B .

As shown in more detail in Figure 4, here with reference to the downstream rectilinear conveyor 40B, each rectilinear conveyor 40A, 40B comprises a sliding track 42 comprising a groove 43 which is delimited by a pair of rectilinear rails 44. The sliding track 42 is intended to receive the preforms 26 in suspension and to guide them in sliding along a rectilinear path "R2", referenced "R1" for upstream rectilinear conveyor 40A. As shown in Figure 5, the body 33 of the preform 26 is received in suspension between the rails 44 on which the collar 34 of the preform 26 rests in a sliding manner. Each sliding track 42 has an upstream end 45 and an upstream end 46 downstream.

The spacing between the rails 44 is set to be slightly greater than the diameter D2 under the neck of the preforms 26. The clearance between the rails 44 and the body 33 of the preforms 26 is sufficient to allow the sliding of the preforms 26 without jamming, while being weak enough to prevent the passage of the collar 34 and the fall of the preforms 26.

In a non-limiting manner, the width between the two rails 44 is adjustable to allow the conveyors 40A, 40B to be adapted to preforms 26 of different dimensions.

As will be explained in more detail below, each rectilinear conveyor 40A, 40B further comprises preform drive members 26 towards the downstream end 46 of the sliding track 42. The driving members are designed to provide each preform 26 directly with a driving force over the entire length of their rectilinear path "R1", "R2".

Referring again to Figure 2, the first rectilinear accumulation conveyor 40A is arranged upstream of the second rectilinear accumulation conveyor 40B. More particularly, the downstream end 46 of the upstream rectilinear conveyor 40A is connected to the upstream end 45 of the downstream rectilinear conveyor 40B.

To allow the accumulation circuit 30 to take up less space and to allow greater freedom of arrangement of the installation, the accumulation circuit 30 comprises an intermediate accumulation conveyor 48, hereinafter called intermediate conveyor 48, which is interposed between the upstream rectilinear conveyor 40A and the downstream rectilinear conveyor 40B.

The intermediate conveyor 48 makes it possible to introduce a bend in the circuit 30 of accumulation. Thus, the rectilinear path "R1" of the upstream rectilinear conveyor 40A forms with the rectilinear path "R2" of the downstream conveyor 40B an angle, called angle "α" of turn, different from 180°. In the example represented in FIG. 2, said angle "α" of turn is approximately equal to 90°.

As a variant, said angle "α" of turn is less than or equal to 90°.

In a particular case represented in FIG. 6, the rectilinear path "R1" of the upstream rectilinear conveyor 40A forms with the rectilinear path "R2" of the downstream conveyor 40B an angle "α" of turn of 0° so that said paths "R1 ", "R2" rectilinear are parallel, the preforms 26 being intended to make a 180° turn in the intermediate conveyor 48.

According to another variant of the invention represented in FIG. 7, the rectilinear path “R1” of the upstream rectilinear conveyor 40A forms with the rectilinear path “R2” of the downstream conveyor 40B an angle “α” of turn greater than 90°.

The intermediate conveyor 48 is also provided with means for driving the preforms 26 downstream. This prevents the preforms 26 from becoming blocked, which would be the case if the preforms 26 were only pushed by the preforms 26 coming from the upstream conveyor 40A.

There is shown in more detail in Figure 8 the intermediate accumulation conveyor 48 which equips the accumulation circuit 30 of Figure 2.

The intermediate accumulation conveyor 48 comprises a track 50 for sliding the preforms 26 straightened in line along an arcuate path "C", that is to say in the form of an arc of a circle, which here extends in a substantially horizontal plane. See Figure 8. The arcuate path "C" is here symbolized by a dotted line which corresponds to the passage of the axis "A" of the preforms 26.

The sliding track 50 more particularly has a groove 52 which is delimited between two rails 54, 56. The groove 52 has the same width as the groove 43 of the straight conveyors 40A, 40B.

The arcuate path "C" presents an arcuate shape centered on a central vertical "B" axis. The arcuate path "C" extends here over an angular sector "β" which, expressed in degrees, is equal to the difference between 180° and the angle "α" of turn (expressed in degrees) (β=180- α). The angular sector "β" is here approximately 90°. The angular sector "β" has been represented in FIG. 8 as being delimited by two fictitious rays "r1" and "r2" extending from the axis "B".

As a variant, the angular sector "β" can be between 90° and 180°. As a variant, the arcuate path "C" extends over an angle greater than or equal to 180° and, of course, strictly less than 360°.

The groove 52 is delimited radially outwards by a first outer fixed rail 54 in the shape of an arc of a circle centered on the central axis "B" and it is delimited radially inwards by a portion of a second rail 56 ring-shaped rotating centered on the central "B" axis. The rotating rail 56 is mounted internally with respect to the curvature of the fixed rail 54.

The fixed rail 54 extends over the angular sector "β" corresponding to that of the arcuate path "C". In a non-limiting manner, the fixed rail 54 is advantageously fixed in a removable manner in order to be able to be replaced by another fixed rail 54 extending over a different angular sector when it is desired to vary the angular sector of the arcuate path "C". . In addition, such a removable fixed rail 54 advantageously makes it possible to vary the width of the groove 52 according to the dimensions of the preforms 26 to be conveyed.

The rotating rail 56 is rotated about the central "B" axis. The rotating rail 56 is for example fixed to the periphery of a wheel 58 which is mounted to rotate around the central axis "B.

The rotating rail 56 here has an outside diameter which is less than the length of the rectilinear path "R1, R2" of each of the upstream and downstream rectilinear conveyors 40A, 40B. The outside diameter of the rotating rail 56 is for example between 0.5 m and 1 m. This advantageously makes it possible to obtain a very compact storage circuit 30 .

In a non-limiting manner, the rotating rail 56 is here driven in rotation by an electric motor (not shown).

The two rails 54, 56 are arranged at the same height as the rails 44 of the rectilinear conveyors 40A, 40B and they are separated by a radial distance between that of the diameter "D1" of the flange 34 and that of the diameter "D2" under collar. Thus, each preform 26 is intended to be suspended, with its axis "A" substantially vertical, in the groove 52 by pressing its flange 34 on each of the rails 54, 56.

The rotating rail 56 does not include any means for indexing the position of the preforms 26. Thus, the preforms 26 are free to slide in the sliding track 50 in which they are free to come into contact with each other.

The sliding track 50 has an upstream end 60 for inlet of the preforms 26 which is intended to be connected to the downstream end 46 of the sliding track 42 of the upstream rectilinear conveyor 40A. More specifically, the fixed rail 54 is arranged in the extension of a first rail 44 associated with the upstream rectilinear conveyor 40A, while a second rail 44 is arranged tangent to the rotating rail 56, in the immediate vicinity of the rotating rail 56, with sufficient play to allow rotation of the rotating rail 56, but small enough to allow the preform 26 to pass from the rail 44 to the rotating rail 56 by sliding.

As shown in Figure 8, the radius "r1" delimiting the upstream angular sector "β" passes through the junction between the sliding track 42 of the upstream rectilinear conveyor 40A and the sliding track 50 of the intermediate conveyor 48 . Said radius "r1" is more particularly perpendicular to the rectilinear path "R1" of the upstream rectilinear conveyor 40A.

The sliding track 50 also has a downstream end 62 which is connected to the upstream end 45 of the sliding track 42 of the downstream rectilinear conveyor 40B. More specifically, a first rail 44 of the downstream rectilinear conveyor 40B is arranged in the extension of the fixed rail 54, while a second rail 44 is arranged tangent to the rotating rail 56, in the immediate vicinity of the rotating rail 56, with a play sufficient to allow the rotation of the rotating rail 56, but small enough to allow the preform 26 to pass from the rotating rail 56 to the rail 44 by sliding.

As shown in Figure 8, the radius "r2" delimiting the downstream angular sector "β" passes through the junction between the sliding track 42 of the downstream rectilinear conveyor 40B and the sliding track 50 of the intermediate conveyor 48 . Said radius "r2" is more particularly perpendicular to the rectilinear path "R2" of the downstream rectilinear conveyor 40B.

To enable the preforms 26 to be conveyed downstream, as indicated by the arrow "F1" in FIG. 8, means are provided for pushing the preforms 26 in the direction of the downstream end 62 along the track 50 slippage.

The rotating rail 56 is part of the means for pushing the preforms 26 towards the downstream end 62 by friction between the rotating rail 56 and the flange 34. To this end, the rotating rail 56 is driven in a rotational movement, indicated by the arrow "F2" in FIG. 8 directed in the same direction as the movement "F1" of the preforms 26. The preforms 26 are driven in rotation around their main axis "A" by friction against the rotating rail 56. The preforms 26 are thus moved along the arcuate path "C" in the direction of rotation of the wheel 58 by rolling against the fixed rail 54.

On a downstream end portion of the sliding track 50, the preforms 26 are likely to be accumulated in the accumulation queue 38 when the latter protrudes from the conveyor 40B downstream. The preforms 26 of the line 38 of accumulation move at a distribution speed substantially lower than the running speed of the rotating rail 56. In this case, the rotating rail 56 slides under the collar 34 of the preforms 26 of the line 38 of accumulation.

To improve the speed of movement of the incoming preforms 26 downstream, without disturbing the slower movement of the preforms 26 possibly waiting in the queue 38 of accumulation, it is planned to supplement the means for pushing the preforms 26 with other thrust organs.

The means for pushing the preforms 26 comprise for example friction elements which are intended to be in contact with the preforms 26 and which are rotated around the central axis "B" together with the rail 56 rotating to push the preforms 26 towards the exit by friction. Such friction elements are designed to slide on a preform 26 which is slowed down in a queue 38 of accumulation in order to allow the extension of the queue 38 of accumulation in the track 50 of sliding.

In the examples illustrated in Figures 9 to 12, the friction elements cooperate with the body 33 of the preform 26. In a variant not shown, at least a part of the friction elements cooperate with another part of the preform 26, such as the collar 32 or collar 34.

According to a first variant of the invention which is shown in Figures 9 and 10, the friction elements are formed by bristles 64 of brushes which extend radially projecting towards the rail 54 outside relative to the rotating rail 56. The bristles 64 of the brush are for example fixed in a rim 66 of the wheel 58 from which they extend radially. The bristles 64 of brushes are here arranged all around the wheel 58, as can be seen in figure 10.

As long as the movement of the preforms 26 is free downstream, the rotation of the wheel 58 makes it possible to advance the preforms 26 by friction with the bristles 64. When the preforms 26 arrive in the queue 38 of accumulation, they are temporarily slowed down and/or immobilized. The preforms 26 accumulated at the end of the intermediate accumulation conveyor 48 are then slowed down relative to the speed of rotation of the wheel 58. The bristles 64 bend elastically to slide on their body 33 without creating any blockage. Thus, an end portion of the intermediate accumulation conveyor 48 can accommodate an accumulation queue 38 in which the preforms 26 are packed downstream of the accumulation circuit 30, without however reducing the free movement speed of the preforms. 26 which move from the upstream end 60 to the line 38 of accumulation.

According to a second variant of the invention which is shown in Figures 11 and 12, the friction elements are formed by strips 68 of elastomeric material. The slats 68 extend radially projecting relative to the rotating rail 56. The slats 68 are capable of rubbing against the body 33 of the preforms 26 to cause them to move downstream by rolling without sliding against the fixed rail 54.

When the preforms 26 are slowed down in an accumulation queue 38, the strips 68 move faster than said preforms 26. The strips 68 are therefore designed to slide on the preforms 26 thus slowed down.

These are slats 68 forming circular arc sectors which are spaced circumferentially from each other. A gap 70 between two adjacent slats 68 makes it possible to promote the sliding of the slats 68 on the body of the preforms 26 when the preform 26 is slowed down in the queue 38 of accumulation.

To further promote the sliding of the slats 68 on the preforms 26 of the accumulation line 38, it is possible to mount the retractable slats 68 radially towards the inside of the wheel 58, an elastic member (not shown) being interposed between each slat 68 and the wheel 58 to push the slats 68 radially outwards. Thus, when the preforms 26 are free to slide downstream, the slats 68 occupy their outwardly extended position to effectively rub against the preforms 26, while when the preform 26 is slowed down, the slat 68 is automatically retracted by contact with the preform 26 against the force provided by the elastic member to promote the sliding of the lamella 68 on the preform 26.

It is of course possible to combine the two variant embodiments to obtain a wheel 58 comprising both bristles 64 of brushes and strips 68.

According to a second embodiment which is shown in FIGS. 13 and 14, the moving means comprise a ramp 72 of nozzles 74 arranged along the arcuate path "C" of the preforms 26. Each nozzle 74 is capable of emitting a jet 76 of gas towards the preforms 26 to push them towards the exit 62.

The nozzles 74 are here connected to a controlled reservoir 78 of pressurized gas "P", for example air. The nozzles 74 are here all made in a common pipe 80 which communicates with the tank 78. Thus the nozzles 74 simultaneously emit a jet 76 of gas. The pipe 80 has the shape of an arcuate tube which reproduces the arcuate shape of the fixed rail 54.

The nozzles 74 are here arranged above the fixed rail 54, for example above the necks 32 of the preforms 26. The gas jets 76 are oriented in a substantially tangential direction with respect to the arcuate path "C". They are directed slightly downwards to push the preforms 26 downstream by entering obliquely inside the neck 32.

The nozzles 74 are regularly arranged along the arcuate path "C" and they are sufficient in number so as to produce a generally homogeneous thrust of the preforms 26 all along their arcuate path "C".

When the preforms 26 are free to move downstream, the jets 76 allow them to reach a free speed of movement. When the preforms 26 reach the accumulation queue 38 and they are forced to scroll at a distribution speed lower than the free displacement speed, the jets 76 still ensure the thrust of the preforms 26 downstream without damaging the preforms. 26, the air being simply diverted in another direction by the slowed down preforms 26.

According to a third embodiment of the invention which is represented in FIG. 15, the means for setting in motion comprise suction orifices 82 which are intended to come into contact with the preforms 26 and which rotate together with the rail 56 rotating around the central "B" axis.

The suction orifices 82 are here made in the rim 66 of the wheel 58. The rim 66 more particularly has a plurality of suction orifices 82 which are regularly distributed around the periphery of the wheel 58.

Each suction orifice 82 is intended to come into contact with the bodies 33 of the preforms 26 received in the sliding track 50 . Each suction port 82 is connected to a source (not shown) of vacuum so as to suck in air. When the body 33 of a preform 26 is in contact with a suction orifice 82, the preform 26 undergoes a suction force which presses it against the rim 66. This suction force is sufficient for the wheel 58 to drive a preform 26 moving along arcuate path "C" as long as it is free to move. The suction force is however weak enough for a preform 26 slowed down by its entry into the accumulation line 38 to be able to escape the suction force of the suction orifice 82, the wheel 58 continuing its rotation without said preform 26.

The intermediate conveyor 48 produced according to any one of the embodiments described above advantageously makes it possible to produce an accumulation circuit 30 having a bend capable of accommodating a portion of the accumulation queue 38 without causing untimely blocking of the scrolling of the preforms 26.

Referring again to Figures 2 and 4, in the examples shown in the figures, each of the rectilinear conveyors 40A, 40B is formed by a brush conveyor. An example of such a rectilinear conveyor 40A, 40B is for example described in detail in document FR 3,028,254 A1 to which reference should be made for more details.

As shown in Figures 4 and 5, in such a rectilinear conveyor 40B, the preform drive members comprise at least one element 84 circulating endlessly bears on its outer face a series of brushes 86 which are able to come into contact with the preforms 26 suspended between the rails 44 to drive them by friction along the track 42 sliding from upstream to downstream. Each element 84 circulating endlessly is here formed by a belt. The brushes 86 extend projecting from the outer face. In the example illustrated, each brush 86 comprises a row of superimposed tufts of bristles.

The endlessly circulating element 84 has a taut strand 88 which is arranged parallel to and close to the rectilinear path “R1”, “R2” of the preforms 26 received in the sliding track 42.

Here, the rectilinear conveyor 40A, 40B comprises two elements 84 circulating endlessly, each of the stretched strands 88 of which is arranged transversely facing each other, on either side of the rectilinear path "R1", "R2" of the preforms 26 , parallel to sliding track 42. Thus, the force exerted by the brushes 86 of the two elements 84 circulating endlessly on each preform 26 are balanced, which allows better driving of the preforms 26 in sliding downstream.

The brushes 86 are more particularly intended to come into contact with the body 33 of the preforms 26. For this purpose the brushes 86 of the stretched strand 88 of each element 84 circulating endlessly extend below one of the associated rails 44.

In a variant not shown, at least part of the brushes 86 extends above the rails 44 to rub against the neck 32.

The endlessly circulating element 84 is preferably positioned so that the ends of the bristles of each brush 86 of the taut strand 88 enter the space swept by the body 33 of the preforms 26 moving from upstream to downstream along the track. 42 slip. Due to their flexibility, the bristles of the brushes 86 undergo, in contact with the body 33 of the preforms 26, a bending which puts the bristles under tension and thereby transmits a force to the preform 26, tending to cause the preform 26 to move.

Each element 84 circulating endlessly is received around two end wheels 90 with a vertical axis. At least one of the wheels 90 is driven to cause the scrolling of the endlessly circulating element 84 so that its taut side 88 scrolls from upstream to downstream.

The endlessly circulating element 84 is moved by the rotation of the drive wheel 90 at a determined speed. The speed of movement of the endlessly circulating element 84 is controlled, here automatically by an electronic control unit (not shown). The speed of movement of the two elements 84 circulating without end of the rectilinear conveyor 40A, 40B is synchronized. Thus, hereinafter, the term “running speed of the brush conveyor” will be used to refer to the speed at which the stretched strand 88 of the elements 84 traveling endlessly from said rectilinear conveyor 40A, 40B scrolls.

As long as the movement of the preforms 26 is not blocked downstream, the scrolling of the elements 84 circulating endlessly makes it possible to advance the preforms 26 by friction with the brushes 86. When the preforms 26 arrive at the end of the conveyor 40A, 40B rectilinear, they are temporarily slowed down or immobilized in the line 38 of accumulation.

As shown in Figure 4, the downstream end rectilinear conveyor 40B includes for example a retractable locking finger 94 to regulate the distribution of the preforms 26 accumulated in the queue 38 of accumulation. The finger 94 is for example mounted to slide transversely between an active position in which it is extended across the path "R2" of the preforms 26, as shown in broken lines, at the downstream end 46 of the sliding track 42 to block the sliding of the preforms 26, and a retracted position, shown in solid lines, in which it is located outside the path "R2" of the preforms 26 to allow the sliding of the preforms 26 in the downstream direction.

When the locking finger 94 is in the active position, the preforms 26 accumulated at the end of the rectilinear conveyor 40B at the downstream end are then slowed down, or even immobile, relative to the speed of the elements 84 circulating endlessly, the brushes 86 bending to slide on their body 33 without blocking the scrolling of the elements 84 circulating endlessly. Thus, a downstream end portion of the rectilinear downstream end conveyor 40B accommodates the accumulation queue 38 in which the preforms 26 are packed.

As a variant, at least the upstream rectilinear conveyor 40A with brushes is replaced by a rectilinear pneumatic conveyor 40A. Such a rectilinear accumulation conveyor 40A comprises rails 44 similar to those of the brush conveyor 40B both in their structure and in their arrangement. However, the preform drive members 26 are no longer belts provided with brushes, but nozzles which are capable of emitting gas jets.

As shown in Figures 16 and 17, the pneumatic conveyor 40A comprises a rectilinear gas pipe 96, a lower wall 98 of which is arranged above the groove 43. The pipe 96 extends along the rectilinear conveying path "R1". . The lower wall 98 comprises blowing nozzles 100, also called vents, distributed along the rectilinear conveying path "R1" which produce a jet 102 of gas, at least one component of which extends in the direction of movement of the preforms 26 in the groove 43 to push the necks 32 of the preforms 26 along the rectilinear conveying path "R1".

Bottom wall 98 includes nozzles 100 which are longitudinally aligned. The nozzles 100 are intended to be arranged above the neck 32 of the preforms 26 received in the groove 43.

All the nozzles 100 are separated longitudinally by the same determined pitch along the rectilinear conveying path "R1", as can be seen in FIG. 16.

The gas here is formed by air which is injected into line 96 by a fan (not shown).

During operation of the manufacturing installation 24 produced according to the teachings of the invention, the accumulation queue 38 begins to form in a downstream end portion of the downstream rectilinear conveyor 40B. To this end, the flow rate of preforms 26 exiting the alignment and straightening device 25 is set to be greater than the rate of distribution of preforms 26 to the transfer wheel 29 .

Depending on the temporary blockages occurring in the alignment and straightening device 25, the accumulation line 38 is likely to lengthen until it completely fills the rectilinear path "R2" of the downstream rectilinear conveyor 40B, then to extend into the arcuate "C" path of the intermediate conveyor 48. It is also possible to completely fill the arcuate path "C" so that the accumulation line 38 extends from the downstream end 46 of the downstream conveyor 40B to a downstream end portion of the upstream rectilinear conveyor 40A.

The length of the accumulation line 38 is then capable of being regulated, for example by controlling the flow of preforms coming from the alignment and straightening device 25 .

The accumulation circuit 30 produced according to the teachings of the invention makes it possible to easily adapt the geometry of the accumulation circuit 30 according to the space available to install the manufacturing installation 24 .

The accumulation circuit 30 produced according to the teachings of the invention makes it possible in particular to obtain a manufacturing installation 24 that is more compact than an installation equipped with an accumulation circuit produced according to the state of the art.

In addition, the accumulation circuit 30 produced according to the teachings of the invention makes it possible to produce an accumulation line in which the preforms 26 are kept aligned and straightened while being able to move in contact with each other. The accumulation circuit 30 produced according to the teachings of the invention makes it possible in particular to prevent the preforms from jamming, in particular in the portion of the arcuate path "C".

As a variant, it is possible to take advantage of the presence of the intermediate accumulation conveyor 48 to integrate therein preform processing devices during their pick-up in the intermediate conveyor. Without limitation, the processing operations concerned are, for example, one or more of the following processing operations:

- dedusting of the interior of the preforms, for example by means of blowing cannulas;

- quality control of the preforms, for example using optical means or cameras;

- the decontamination of the preforms, for example by exposure to ultraviolet radiation and/or by injection of decontaminating agents into the preforms.

Claims (13)

Circuit (30) for accumulating preforms (26) aligned and straightened, in particular preforms (26) made of thermoplastic material, in an accumulation line (38) comprising at least two rectilinear accumulation conveyors (40A, 40B) arranged in series each comprising:
- a sliding track (42) delimited by a pair of rectilinear rails (44) intended to receive the preforms (26) in suspension and to guide them in sliding along a rectilinear path (R1, R2);
- drive members of the preforms (26) downstream of the sliding track (42);
characterized in that it comprises an intermediate accumulation conveyor (48) which is interposed between the upstream rectilinear conveyor (40A) and the downstream rectilinear conveyor (40B), the intermediate conveyor (48) comprising:
- a track (50) for sliding the preforms (26) along an arcuate path (C) in the shape of an arc of a circle, the track (50) for sliding being delimited by a first rail (54) fixed in the shape of a circular arc and by a second annular rotating rail (56), the rotating rail (56) being driven in rotation about a central axis (B) which is arranged at the center of the circular arc;
- an end (60) upstream of the inlet of the sliding track (50) being connected to a downstream end (46) of the sliding track (42) of the straight upstream conveyor (40A);
- a downstream end (62) of the slip track (50) output being connected to an upstream end (45) of the slip track (42) of the straight downstream conveyor (40B). Accumulation circuit (30) according to the preceding claim, characterized in that the rectilinear path (R1) of the rectilinear upstream conveyor (40A) forms with the rectilinear path (R2) of the rectilinear downstream conveyor (40B) a different angle (α) 180°. Accumulation circuit (30) according to the preceding claim, characterized in that the rectilinear path (R1) of the rectilinear upstream conveyor (40A) forms with the rectilinear path (R2) of the rectilinear downstream conveyor (40B) an angle (α) less or equal to 90°. Accumulation circuit (30) according to the preceding claim, characterized in that the rectilinear path (R1) of the rectilinear upstream conveyor (40A) forms with the rectilinear path (R2) of the rectilinear downstream conveyor (40B) an angle of 0° of so that said rectilinear paths (R1, R2) are parallel. Accumulation circuit (30) according to Claim 2, characterized in that the rectilinear path (R1) of the rectilinear upstream conveyor (40A) forms with the rectilinear path (R2) of the rectilinear downstream conveyor (40B) an angle greater than 90° . Accumulation circuit (30) according to any one of the preceding claims, characterized in that at least one of the rectilinear conveyors (40A, 40B) is formed by a brush conveyor whose drive members are formed by at least one element (84) circulating endlessly, one outer face of which carries a series of brushes (86) intended to come into contact with the preforms (26) in suspension to drive them downstream along the track (42) of slippage. Accumulation circuit (30) according to any one of the preceding claims, characterized in that at least one of the rectilinear conveyors (40A, 40B) is a pneumatic conveyor which comprises blowing nozzles (100) distributed along of the conveying path (R1, R2) which are capable of emitting a jet (102) of gas in the direction of movement of the preforms (26) to push them along the rectilinear path (R1, R2). Accumulation circuit (30) according to any one of the preceding claims, characterized in that the intermediate conveyor (48) comprises complementary means for pushing the preforms (26) in the direction of the downstream end (62) of the outlet of the the sliding track (50). Accumulation circuit (30) according to the preceding claim, characterized in that the intermediate conveyor (48) comprises friction elements which are intended to be in contact with the preforms (26) and which are driven in rotation around the central axis (B) together with the rail (56) rotating to push the preforms (26) towards the end (62) downstream of the outlet by friction. Accumulation circuit (30) according to the preceding claim, characterized in that the rotating rail (56) and the friction elements are carried by a common wheel (58). Accumulation circuit (30) according to the preceding claim, characterized in that, at least in part, the friction elements are formed by bristles (64) of brushes which extend radially projecting with respect to the rail (56) turning. Accumulation circuit (30) according to any one of Claims 10 or 11, characterized in that, at least in part, the friction elements are formed by strips (68) of elastomeric material which extend radially projecting relative to the rotating rail (56). Accumulation circuit (30) according to any one of Claims 8 to 13, characterized in that the intermediate conveyor (48) comprises a ramp of nozzles (74) arranged along the arcuate path (C) of the preforms (26) , the nozzles (74) being capable of emitting a jet (76) of gas towards the preforms (26) to push them towards the end (62) downstream of the outlet.