FR3097214A1 - Preform accumulation circuit comprising at least two brush conveyors arranged in series - Google Patents

Abstract

The invention relates to a circuit (28) for accumulating aligned and straightened preforms (12), in particular preforms (12) made of thermoplastic material, in an accumulation line (23) comprising a conveyor (30A) with brushes. downstream end comprising: - a sliding track (22A) intended to receive the preforms (12) in suspension; - an element (34A) circulating endlessly, one outer face of which carries a series of brushes (36A) coming into contact with the preforms (12) in suspension to drive them downstream along the sliding track (22A), characterized in that the preform accumulation circuit (28) comprises at least a second conveyor (30B) with upstream brushes similar to the conveyor (30A) with downstream end brushes including a downstream end (35B) of the track (22B) slide is connected directly in series with an upstream end (33A) of the slide track (22A) of the downstream end brush conveyor (30A). Figure for the abstract: Figure 2

Description

"Preform accumulation circuit comprising at least two brush conveyors arranged in series"

Technical field of the invention

The invention relates to a preform accumulation circuit intended to be arranged at the outlet of a preform alignment and straightening device in order to be able to continuously supply an installation for manufacturing containers, in particular bottles.

Technical background

The accumulation circuit is intended to be implemented in an installation for manufacturing 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 stages. 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.

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 location. 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 blowing station therefore has a preform feed device which is equipped with a device for aligning the preforms in a row and straightening them. The present invention relates to such a device.

The present invention relates more particularly to a device for aligning and straightening preforms in which the preforms are not indexed in position. Most of the time, the preforms come out in close line, each preform being in contact with the next preform. This makes it possible to guarantee an efficient supply to the following treatment stations.

However, it happens that the preforms of the outgoing queue are not in contact with each other. A hole is then created which is liable to disturb the supply of the following stations. The yield of the manufacturing installation is then likely to drop. This is all the more likely to occur when the throughput of bottles processed by the installation is high.

The invention proposes a circuit for accumulating aligned and straightened preforms, in particular preforms made of thermoplastic material, in an accumulation queue comprising a downstream end brush conveyor comprising:

- A sliding track delimited by a pair of rails intended to receive the preforms in suspension;

- At least one endless circulating element, one outer face of which carries a series of brushes intended to come into contact with the preforms in suspension at a determined running speed to drive them downstream along the sliding track.

The accumulation circuit of the invention is characterized in that the preform accumulation circuit comprises at least one second upstream brush conveyor similar to the downstream end brush conveyor of which a downstream end of the sliding track is connected directly in series with an upstream end of the downstream end brush conveyor slide track.

According to other characteristics of the accumulation circuit produced according to the teachings of the invention:

- the accumulation circuit comprises at least one second upstream brush conveyor similar to the downstream end brush conveyor, a downstream end of the sliding track of which is connected directly in series with an upstream end of the sliding track of the first conveyor with upstream brushes;

- the running speed of the endless circulating elements of each brush conveyor of the accumulation circuit can be controlled individually;

- all the brush conveyors of the accumulation circuit have a track of identical length;

- the downstream end brush conveyor has a retractable blocking finger to regulate the distribution of the preforms accumulated in the accumulation queue;

- each brush conveyor comprises a pair of parallel guide rails delimiting the sliding track, the transverse spacing of the rails being independently adjustable for each brush conveyor.

The invention also relates to a method for controlling the accumulation circuit produced according to the teachings of the invention, characterized in that when the accumulation line extends at least to the upstream end of the sliding track of the downstream end brush conveyor, the downstream end brush conveyor is controlled at a nominal running speed.

According to other characteristics of the ordering process:

- when the accumulation line extends into one of the upstream brush conveyors, but does not reach the upstream end of said upstream brush conveyor, said upstream brush conveyor is controlled at a nominal running speed ;

- the nominal running speed of each upstream brush conveyor is greater, for example by 30%, than the nominal running speed of the downstream end brush conveyor;

- when the accumulation line reaches at least the upstream end of one of the upstream brush conveyors, said upstream brush conveyor is controlled at a slowed-down running speed which is lower than its nominal running speed;

- when the accumulation line does not reach the upstream end of the downstream end brush conveyor, all the brush conveyors of the accumulation circuit are controlled to operate at an accelerated running speed which is greater than their speed of respective nominal scroll;

- the accelerated running speed of each brush conveyor is equal to their respective nominal running speed multiplied by an acceleration factor greater than 1 of the same value.

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 side view which represents a preform intended to be taken over by the accumulation circuit produced according to the teachings of the invention.

FIG. 2 is a schematic top view which represents an accumulation circuit produced according to a first embodiment of the invention which comprises two brush conveyors.

FIG. 3 is a perspective view which represents a brush conveyor which equips the accumulation circuit produced according to the invention.

Figure 4 is a cross-sectional view along section plane 4-4 of Figure 3.

FIG. 5 is a detail view which shows the end of the rails of the conveyor with brushes at the downstream end of the accumulation circuit produced according to the teachings of the invention which are equipped with means for adjusting their spacing.

FIG. 6 is a view of a downstream end section of the rails of the downstream end brush conveyor of the accumulation circuit of the invention which is equipped with a locking pin which makes it possible to regulate the distribution of the preforms from the downstream accumulation queue.

FIG. 7 is a view similar to that of FIG. 2 which represents a second embodiment of the invention in which the accumulation circuit comprises three brush conveyors arranged in series.

Figure 8 is a top view showing an upstream end of the rails of the downstream end brush conveyor of either of the two embodiments of the invention which is equipped with an accumulation lane sensor.

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 following local orientations will be adopted without limitation for each preform:

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

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

- transverse "T" directed orthogonally to the two previous orientations.

There is shown in Figure 1 an example of a preform 12 intended to be used in the accumulation circuit produced according to the teachings of the invention. Such a preform 12 is made of thermoplastic material, here of PET. It is conventionally obtained by injection molding. It has a substantially axisymmetric shape around a main axis "A" shown vertically in Figure 1.

It comprises a body 14 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. 1, a neck 16 that is axially open.

The preform 12 also comprises a face 18 of annular support, here located under a flange, which is oriented axially towards the closed end of the preform 12, which projects radially with respect to the rest of the body 14, and which is arranged above above a center "G" of gravity of the preform 12.

The term “annular” means that the support face goes around the preform 12 either continuously or discontinuously. In the latter case, the annular face is for example formed of separate segments which go around the preform 12 which are nevertheless sufficiently close together so that the preform 12 can be supported between two diametrically opposed supports whatever the position of the preform 12 around its main axis.

In the example shown, the base of the neck 16, at the junction with the body 14, has a collar which extends radially projecting with respect to the rest of the preform 12. The lower face of the collar thus forms said face 18 support.

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

According to another variant, the support face is for example formed by a lower face of a thread of the neck.

According to yet another variant, the support face is attached to the preform 12, for example by means of a plug.

An external diameter "D1" of the support face 18, in this case of the collar, is thus greater than a diameter "D2" under the neck of the body 14, measured directly below the collar.

The neck 16 has its final shape, while the body 14 is intended to be stretched during a subsequent forming operation to form the body of the finished container. For this purpose, the installation is equipped with a heating station which is arranged downstream of the device 10 for alignment and straightening.

Furthermore, the weight of the body 14 of the preforms 12 used is greater than the weight of the neck 16, including that of the collar. Thus, the center "G" of gravity of the preform 12 is located under the support face 18 with reference to FIG. 1. Thus, a preform 12 supported by its support face 18 while resting on two diametrically opposite supports will be oriented naturally by gravity col 16 at the top.

The example shown in Figure 1 is non-limiting. It will be understood that the invention is intended to be applied to any type of preforms 12 having a support face 18 projecting radially with respect to the rest of the body 14, and having a center of gravity offset axially towards the body with respect to said face. 18 bracket.

Conventionally, the raw injection preforms 2 are initially stored in bulk in a container. They are then straightened and aligned by known means, for example by a gravity rail or by a centrifuge bowl 20 such as that described in document WO 2016/166459 A1, as shown in Figure 2.

On leaving the straightening and alignment device 20, the aligned and straightened preforms 12 are directed in line towards a linear sliding track 22 delimited by two rails where they are accumulated in an accumulation line 23 by pushing each other. the others against a temporary controlled stopping point.

In certain critical zones, in particular at the junction between the alignment and straightening device 20 and the track 22, or in a final section of the alignment and straightening device, means are generally provided for preventing preforms from jamming. 12 badly positioned. The preforms 12 that are incorrectly positioned in the straightening and alignment device are then reintroduced at the entry into the latter.

For example, when the alignment and straightening device 20 is formed by a centrifuge bowl, such means are formed by paddle wheels, also called disentangling wheels, such as those described in document WO 2016/166446 A1.

When a badly positioned preform 12 is ejected, this causes a temporary blocking of the line of straightened and aligned preforms, for example for a few seconds. As a result, the flow of preforms 12 leaving the alignment and straightening device 20 is not constant. It follows that the preforms 12 do not necessarily arrive grouped on the linear track 22, trains 24 spaced out of preforms can then be formed, as illustrated in Figure 2.

The preforms 12 of the accumulation queue 23 are intended to be introduced into a heating unit 26 so that their body there undergoes thermal conditioning by exposure to sources of electromagnetic radiation (for example infrared), so as to be softened with a view to being formed into containers by blow molding or stretch blow molding in a forming unit equipped with molds with the imprint of the containers.

From the inlet of the heating unit 26 to the forming unit, the preforms 12 are handled individually by gripping means (such as spinners or pliers). 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 12 in the associated molds, so that in l 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.

This is why an accumulation circuit 28 as shown in FIG. 2 is interposed between the output of the alignment and straightening device 20 and the heating unit 26 . The accumulation circuit 28 comprises in particular a conveyor 30A with downstream end brushes. This is an accumulation conveyor 30A designed to, from trains 24 of spaced preforms 12 arriving from the alignment and straightening device 20, form a line 23 of continuous accumulation of adjacent preforms 12 intended to be taken individually supported. Such a conveyor 30A with downstream end brushes is for example described in detail in the document FR 3,028,254 A1 to which reference will be made.

As shown in Figures 3 and 4, the downstream end brush conveyor 30A includes a sliding track 22A formed by a pair of parallel support rails 32A, called "support 29" in the cited document, which extends from an upstream end 33A to a downstream end 35A.

The body 14 of the preform 12 is received in suspension between the rails 32A on which the collar 18 of the preform 12 rests in a sliding manner. The spacing between the rails 32A is adjusted to be slightly greater than the under-neck diameter D2 of the preforms 12 The play between the rails 32A and the body 14 of the preforms 12 is sufficient to allow the sliding of the preforms 12 without jamming, while being small enough to prevent the passage of the flange 18 and the fall of the preforms 12.

The sliding track 22A makes it possible to guide the preforms 12 along a determined path. This is a straight path.

At least one element 34A circulating endlessly carries on its outer face a series of brushes 36A which are able to come into contact with the preforms 12 in suspension between the rails 32A to drive them by friction along the sliding track 22A d upstream downstream. Each element 34A circulating endlessly is here formed by a belt. The brushes 36A extend projecting from the outer face. In the example illustrated, each brush 36A comprises a row of superimposed tufts of bristles.

The endless circulating element 34A has a stretched strand 38A by means of tensioning rollers 40A and a holding plate 41A. The stretched strand 38A is arranged parallel to and close to the path of the preforms 12 received in the sliding track 22A.

Here, the conveyor 30A with downstream end brushes comprises two elements 34A circulating endlessly, each of the stretched strands 38A of which is arranged transversely facing each other, on either side of the path of the preforms 12, parallel to the track 22A guide. Thus, the force exerted by the brushes 36A of the two elements 34A circulating endlessly on each preform 12 are balanced, which allows better driving of the preforms 12 in sliding downstream.

The brushes 36A are more particularly intended to come into contact with the body 14 of the preforms 12. For this purpose the brushes 36A of the stretched strand 38A of each element 34A circulating endlessly extend below one of the associated rails 32A.

In a variant not shown, at least part of the brushes 36A extends above the rails 32A to rub against the neck 16.

The element 34A circulating endlessly is preferably positioned so that the ends of the bristles of each brush 36A of the stretched strand 38A enters the space swept by the body 14 of the preforms 12 moving from upstream to downstream along the track. 22A slip. Due to their flexibility, the bristles of the brushes 36A undergo, in contact with the body of the preforms, a bending which puts the bristles under tension and thereby transmits a force to the preform 12, tending to cause the preform 12 to move. According to a preferred embodiment, the bristles enter the space swept by the body of the preforms with a depth of 0.5 and 3 mm, and for example of the order of 1 mm.

Each endless circulating element 34A is received stretched around two vertical axis end wheels 42A. At least one of the wheels 42A is driven to drive the scrolling element 34A circulating endlessly so that its stretched strand 38A scrolls from upstream to downstream.

The endlessly circulating element 34A is moved by the rotation of the drive wheel 42A at a determined speed. The speed of movement of the endlessly circulating element 34A is controlled, here automatically by an electronic control unit 44. The speed of movement of the two endless circulating elements 34A of the downstream end brush conveyor 30A is synchronized. Thus, hereafter, the term "running speed of the brush conveyor" will be used to refer to the speed at which the stretched strand 38A of the elements 34A traveling endlessly from said conveyor 30A with downstream end brushes runs.

As represented in FIG. 5, provision is made to allow adjustment of the spacing of the rails 32A of the conveyor 30A with downstream end brushes so as to adapt it to batches of preforms having varied diameters D2 under the neck. For example, each rail 32A is carried by a frame 46 fixed with respect to the ground on which it is fixed by means of several plates 48A integral with the rail 32A, one of which is shown in FIG. 5. The plate 48A has an orifice 50A oblong extending in a transverse direction, while the frame has a hole arranged in coincidence with the hole 50A oblong. A fixing screw 52 is received in each oblong hole 50A and in the coinciding hole of the frame 46. It is thus possible to move the rail 32A transversely relative to the screw 52, then to immobilize the rail 32A relative to the frame 46 in a position chosen by tightening the screw 52.

Similarly, provision is made to be able to adjust the spacing between the two stretched strands 38A of the elements 34A circulating endlessly for the same reasons. The adjustment is made in the same way by means of screws 52 received in associated oblong holes 50 as shown in Figure 3.

As long as the movement of the preforms 12 is not blocked downstream, the scrolling of the endless circulating elements 34A makes it possible to advance the preforms 12 by friction with the brushes 36A. When the preforms 12 arrive at the end of conveyor 30A with downstream end brushes, they are temporarily slowed down or immobilized while waiting to be picked up by an indexed gripping member, such as a notch or a clamp of a wheel 54 transfer.

As represented in FIG. 6, the conveyor 30A with downstream end brushes comprises, for example, a retractable blocking finger 56 forming the temporary stopping point 25 to regulate the distribution of the preforms 12 accumulated in the line 23. The finger 56 is for example mounted to slide transversely between an active position in which it is extended across the path of the preforms 12, as represented by n dashed lines, at the downstream end 35A of the sliding track 22A to block the sliding of the preforms 12, and a retracted position, shown in solid lines, in which it is located outside the path of the preforms 12 to allow the sliding of the preforms 12 in the downstream direction.

When the locking finger 56 is in the active position, the preforms 12 accumulated at the end of the conveyor 30A with downstream end brushes are then slowed down, or even stationary, relative to the speed of the elements 34A circulating endlessly, the brushes 36A bending to slide on their body 14 without blocking the scrolling of the endless circulating elements 34A. Thus, a downstream end portion of the conveyor 30A with downstream end brushes accommodates the accumulation line 23 in which the preforms 12 are packed.

For the transfer wheel 54 to be supplied in an optimal manner, the line 23 for accumulating preforms 12 must constantly have a length greater than a critical threshold, for example greater than 1 meter. The length must in particular be sufficient to guarantee that the flow of preforms 12 remains continuous in the heating unit 26 even when flow interruptions are caused by an operation to eject a preform that is incorrectly positioned in the alignment device 20 and recovery.

However, in some cases, the presence of holes in the line of preforms 12 exiting from the alignment and straightening device 20 causes a deficit of preforms 12 in the line 23 of accumulation of preforms 12.

The invention proposes a circuit 28 for accumulating preforms comprising at least one second conveyor 30B with upstream brushes.

Each upstream brush conveyor 30B has a structure similar to that of the downstream end brush conveyor 30A. The same reference numbers will therefore be used followed by the letter B instead of the letter A to designate elements identical to those of the downstream end conveyor 30A on the upstream conveyor 30B.

A downstream end 35B of the slide track 22B of the upstream conveyor 30B is connected directly in series with the upstream end 33A of the slide track 22A of the downstream end brush conveyor 30A, as shown in Figure 2.

In the example represented in FIG. 2, the accumulation circuit 28 comprises two brush conveyors, comprising the downstream end conveyor 30A and a single upstream conveyor 30B.

Alternatively, the accumulation circuit 28 comprises more than two brush conveyors arranged in series. Thus, in the example represented in FIG. 7, the accumulation circuit 28 has three brush conveyors, namely the downstream end brush conveyor 30A and two upstream brush conveyors 30B, 30C.

Each of the circuit's brush conveyors 30A, 30B, 30C have a sliding track 22A, 22B, 22C of identical length. Thus, in the example represented in FIG. 2, the circuit 28 of accumulation comprising two conveyors 30A, 30B with brushes makes it possible to double the length of the queue 23 of accumulation, while in the example represented in FIG. , the accumulation circuit 28 comprising three conveyors 30A, 30B, 30C with brushes makes it possible to triple the length of the queue 23 of accumulation.

Each upstream brush conveyor 30B, 30C also includes a pair of guide rails 32B, 32C defining a sliding track 22B, 22C. The rails 32B, 32C of each of the brush conveyors 30A, 30B, 30C are separate from the rails of the other brush conveyors. The width of the sliding track 22A, 22B, 22C is thus advantageously adjustable independently for each brush conveyor 30A, 30B, 30C.

The upstream end 33A, 33B of the rails of a brush conveyor 30A, 30B is arranged directly in the extension of the downstream end 35B, 35C of the rails of the brush conveyor arranged directly upstream.

In a variant not shown, intermediate rails are interposed between the upstream end of the rails of a brush conveyor and the downstream end of the rails of the brush conveyor arranged directly upstream. There is thus a junction zone between two adjacent brush conveyors in which the preforms slide towards the downstream brush conveyor due to the effect of their inertia without being stressed by external means.

The path of the preforms along the accumulation circuit 28 takes place here in a straight line passing through the various brush conveyors.

In a variant of the invention, not shown, the brush conveyors are interconnected by curved intermediate rails which make it possible to confer a non-rectilinear shape on the path of the preforms in the accumulation circuit.

The running speed of each brush conveyor 30A, 30B, 30C of the accumulation circuit 28 can be controlled individually.

The invention also proposes a method for controlling the brush conveyors 30A, 30B, 30C of such an accumulation circuit 28.

When the accumulation line 23 extends from the downstream end 35A of the downstream end brush conveyor 30A at least to the upstream end 33A of the downstream end brush conveyor 30A of the accumulation circuit 28 , the downstream end brush conveyor 30A is controlled to operate at a nominal running speed "VA1". This running speed makes it possible to guarantee an optimal thrust of the preforms 12 on the last preform 12 of the queue 23 of accumulation in order to ensure the correct supply of the wheel 54 of transfer.

When the accumulation line 23 extends to the sliding track 22B, 22C of one of the upstream brush conveyors 30B, 30C, but does not reach the upstream end 33B or 33C of said conveyor 30B or 30C with upstream brushes, said upstream brush conveyor is controlled at a nominal running speed "VB1" or "VC1".

The nominal running speed "VB1" or "VC1" of the upstream brush conveyor 30B, 30C is higher than the nominal running speed "VA1" of the downstream end brush conveyor. For example, the nominal running speed "VB1" or "VC1" of the upstream brush conveyor 30B, 30C is 30% higher than the nominal running speed "VA1" of the downstream end brush conveyor. This makes it possible to quickly convey the preforms 12 to the accumulation line 23 to guarantee that the accumulation line is long enough to continuously supply the transfer wheel 54, even at high speed.

When the accumulation line 23 reaches the upstream end 33B, 33C of one of the conveyors 30B, 30C with upstream brushes, said conveyor 30B, 30C with upstream brushes is controlled at a slow running speed "VB2" or "VC2" which is lower than its nominal frame rate "VB1", "VC1".

For example, the idle running speed "VB2" or "VC2" of the upstream brush conveyor 30B, 30C is equal to the nominal running speed "VA1" of the downstream end brush conveyor. The conveyor 30B, 30C being full, it is only necessary to advance the preforms 12 of the accumulation queue downstream, avoiding the creation of holes. A higher scrolling speed would therefore cause unnecessary energy consumption.

When the accumulation line 23 does not reach the upstream end 33A of the downstream end brush conveyor 30A, all the brush conveyors 30A, 30B, 30C are controlled to operate at an accelerated running speed "VA3", "VB3", "VC3" which is higher than their respective "VA1", "VB1", "VC1" rated frame rate. For example, the accelerated running speed "BA3", "VB3" or "VC3" of the brush conveyors 30A, 30B, 30C is equal to their respective nominal running speed "VA1", VB1", VC1" multiplied by the same acceleration factor greater than 1, for example the acceleration factor is equal to 1.1. This accelerated scrolling speed is selected to make it possible to fill the accumulation queue 23 faster than the forward speed required to supply the transfer wheel 54 .

The method is advantageously carried out automatically. To this end, the running speeds of all the conveyors 30A, 30B, 30C are controlled by the electronic control unit 44.

The electronic control unit 44 receives signals from sensors 58 arranged at the upstream end of each conveyor 30A, 30B, 30C of the circuit 28 of accumulation.

Such a sensor 58 is able to detect when the preforms 12 are arranged against each other in the line 23 of accumulation. This is for example a so-called "barrier" sensor 58 which comprises an emitter 60 of an electromagnetic beam 62, for example a light beam, which passes through the path of the preforms 12 in the accumulation circuit 28. The sensor 58 also includes a transducer 64 arranged opposite the emitter 60 and which produces a signal when it is hit by the beam 62. The axis of the beam 62 is inclined with respect to the path of the preforms 12 so as to be constantly interrupted when it is cut by the preforms 12 accumulated against each other, as shown in FIG. 8. Indeed, if the beam 62 were arranged perpendicular to the path of the preforms, it would be likely to pass between the necks or the bodies of two adjacent preforms 12 of the line 23 of accumulation.

When the beam 62 is cut long enough, for example for a few seconds, it is estimated that the sensor 58 detects the presence of preforms accumulated in the line 23 of accumulation.

The invention thus makes it possible to have an accumulation circuit having a sufficient length to allow a bottle manufacturing installation to operate at high speed.

In addition, the accumulation circuit equipped with several brush conveyors arranged directly one after the other makes it possible to speed up the transport of preforms in the accumulation queue while saving energy and minimizing the thrust. of the other preforms on the last preform of the accumulation queue.

Furthermore, such an accumulation circuit is easily adjustable to be adapted to preforms of different dimensions. Indeed, instead of adjusting the spacing of two very long rails, it is possible to individually adjust the spacing of the rails of each brush conveyor.

Claims (12)

Circuit (28) for accumulating preforms (12) aligned and straightened, in particular preforms (12) made of thermoplastic material, in an accumulation line (23) comprising a conveyor (30A) with downstream end brushes comprising:
- a sliding track (22A) delimited by a pair of rails (32A) intended to receive the preforms (12) in suspension;
- at least one element (34A) circulating endlessly, one outer face of which carries a series of brushes (36A) intended to come into contact with the preforms (12) in suspension at a determined running speed to drive them downstream along the sliding track (22A),
characterized in that the preform accumulation circuit (28) comprises at least a second upstream brush conveyor (30B) similar to the downstream end brush conveyor (30A) of which a downstream end (35B) of the track (22B ) sliding is connected directly in series with an upstream end (33A) of the sliding track (22A) of the conveyor (30A) with downstream end brushes. Accumulation circuit (28) according to the preceding claim, characterized in that it comprises at least one second upstream brush conveyor (30C) similar to the downstream end brush conveyor (30A) of which a downstream end (35C) of the sliding track (22C) is connected directly in series with an upstream end (33B) of the sliding track (22B) of the first upstream brush conveyor (30B). Accumulation circuit (28) according to any one of the preceding claims, characterized in that the running speed of the elements (34A, 34B, 34C) circulating endlessly on each brush conveyor (30A, 30B, 30C) of the circuit (28) accumulation is individually controllable. Accumulation circuit (28) according to any one of the preceding claims, characterized in that all the brush conveyors (30A, 30B, 30C) of the accumulation circuit (28) have a track (22A, 22B, 22C) of identical length. Accumulation circuit (28) according to any one of the preceding claims, characterized in that the downstream end brush conveyor (30A) comprises a retractable locking finger (56) to regulate the distribution of the preforms (12) accumulated in the line (23) of accumulation. Accumulation circuit (28) according to any one of the preceding claims, characterized in that each brush conveyor (30A, 30B, 30C) comprises a pair of parallel guide rails (32A, 32B, 32C) delimiting the track ( 22A, 22B, 22C) of sliding, the transverse spacing of the rails (32A, 32B, 32C) being independently adjustable for each conveyor (30A, 30B, 30C) with brushes. Method for controlling the accumulation circuit (28) according to any one of the preceding claims, characterized in that when the accumulation line (23) extends at least as far as the upstream end (35A) of the sliding track (22A) of the conveyor (30A) with downstream end brushes, the conveyor (30A) with downstream end brushes is controlled at a nominal running speed (VA1). Method according to the preceding claim, characterized in that, when the accumulation line (23) extends as far as one of the upstream brush conveyors (30B, 30C), but does not reach the upstream end ( 33B, 33C) of said conveyor (30B, 30C) with upstream brushes, said conveyor (30A, 30B) with upstream brushes is controlled at a nominal running speed (VB1, VC1). Method according to the preceding claim, characterized in that the nominal running speed (VB1, VC1) of each conveyor (30B, 30C) with upstream brushes is higher, for example by 30%, than the nominal running speed (VA1) of the conveyor (30A) with downstream end brushes. Method according to any one of Claims 7 to 9, characterized in that when the accumulation line (23) reaches at least the upstream end (33B, 33C) of one of the upstream brush conveyors (30B, 30C) , said conveyor (30B, 30C) with upstream brushes is controlled at a slow running speed (VB2, VC2) which is lower than its nominal running speed (VB1, VC1). A method according to any one of claims 7 to 10, characterized in that when the accumulation line (23) does not reach the upstream end (33A) of the downstream end brush conveyor (30A), all conveyors (30A, 30B, 30C) with brushes of the accumulation circuit (28) are controlled to operate at an accelerated running speed (VA3, VB3, VC3) which is greater than their nominal running speed (VA1, VB1, VC1 ) respectively. Method according to the preceding claim, characterized in that the accelerated running speed (VA3, VB3, VC3) of each brush conveyor (30A, 30B, 30C) is equal to their respective nominal running speed (VA1, VB1, VC1) multiplied by an acceleration factor greater than 1 of the same value.